Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ARCUATE FIXATION MEMBER
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority to U.S. provisional patent
application
number 61/169,461, filed April 15, 2009, which is incorporated herein by
reference in its
entirety.
TECHNICAL FIELD
[0002] The present disclosure relates generally to orthopedics, and in
particular relates
to fixation systems, intervertebral implants, and associated surgical methods
and procedures for
using same.
BACKGROUND
[0003] Spinal fixation systems such as pedicle screw and rod constructs are
commonly
used to promote fusion between interverterbral bodies. The insertion of
pedicle screws typically
requires a linear "line-of-approach" trajectory that is aligned with the
longitudinal axis of the
screw, in order to accommodate the access and delivery instruments. Similarly,
anchors such as
bone screws may be used to directly fix intervertebral implants to vertebral
bodies, typically
requiring the insertion of several screws at unique angles oblique to the
sagittal and/or transverse
plane, and thus mulitple lines-of-approach. However, in a variety of surgical
situations,
achieving a desired trajectory for screw insertion can be difficult due to the
patient's anatomy
obstructing a linear line-of-approach. For example, medially-directed
placement of pedicle
screws into the sacrum is desirable to prevent screw loosening and/or pullout,
but can be
prohibited due to the iliac crest obstructing the linear line-of-approach.
[0004] In addition to the above-discussed linear line-of-approach problems,
limitations
of the fixation anchors themselves can further limit spinal fixation treatment
approaches. For
example, unilateral spinal fixation procedures, wherein a pedicle screw and
rod construct is
placed on a single side of the spine, provide advantages such as limiting
surgical site morbidity
and shortening surgical time when compared with standard bilateral fixation
procedures wherein
the construct is placed on both sides of the spine and interconnected.
However, unilateral fusion
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constructs typically exhibit decreased mechanical rigidity in comparison to
bilateral constructs,
for example due to lower torsional and/or rotational rigidty and weaker
resistance to screw
pullout forces under physiologic loading when compared to typical bilateral
constructs. As a
result, unilateral fixation procedures are rarely performed in lieu of
bilateral fixation procedures.
[0005] What is therefore desirable are spinal fixation systems that allow for
the creation
of rigid constructs when the linear line-of-approach for insertion of fixation
anchors is
unavailable and/or undesirable (e.g., when multiple anchors are required),
while at the same time
providing increased rigidity and robustness to spinal constructs such as those
used in unilateral
fusion procedures.
SUMMARY
[0006] Arcuate fixation members with varying configurations and/or features
are
disclosed, along with additional components for use therewith in disclosed
fixation systems and
intervertebral implant systems. The arcuate fixation members may be of varying
lengths, cross
sectional geometries, and/or cross sectoinal areas, and may be configured with
various features
such as heads configured to accept other fixation system components, tabs to
allow arcuate
fixation member-in-arcuate fixation member or fixation anchor-in-arcuate
fixation member
configurations. Fixation systems or intervertebral implant systems utilizing
arcuate fixation
members are particularly suitable when a linear line-of-approach for
delivering fixation members
is undesirable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The foregoing summary, as well as the following detailed description of
the
preferred embodiments of the application, will be better understood when read
in conjunction
with the appended drawings. For the purposes of illustrating the arcuate
fixation member
systems and methods, there are shown in the drawings preferred embodiments. It
should be
understood, however, that the instant application is not limited to the
precise arrangements
and/or instrumentalities illustrated in the drawings, in which:
[0008] Figure IA is a front elevation view of an arcuate fixation member
constructed in
accordance with an embodiment;
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[0009] Figure lB is a side elevation view of the arcuate fixation member
illustrated in
Fig. IA;
[0010] Figures IC -IF are cross sectional views illustrating embodiments of
various
example geometries of the arcuate fixation member illustrated in Figures IA
and 1B;
[0011] Figure 1G is a perspective view of an embodiment of an arcuate fixation
member constructed in accordance with another embodiment;
[0012] Figure 1H is a perspective view of a guiding member for receiving an
arcuate
fixation member;
[0013] Figure 2 is a cranial-caudal view of a vertebral body with a pair of
arcuate
fixation members and guiding members inserted therein;
[0014] Figure 3 is a posterior view of the assembly illustrated in Figure 2;
[0015] Figure 4A is a side elevation view of an arcuate fixation member
constructed in
accordance with another embodiment;
[0016] Figure 4B is a top elevation view of the arcuate fixation member
illustrated in
Figure 4A;
[0017] Figure 4C is a side elevation view of an embodiment of the arcuate
fixation
member illustrated in Figure 4A in combination with a fixation anchor;
[0018] Figures 4D and 4E are side elevation views of additional embodiments of
the
arcuate fixation member and fixation anchor illustrated in Figure 4C;
[0019] Figure 4F is a side elevation view of an embodiment of the arcuate
fixation
member illustrated in Figure 4A in combination with an embodiment of the
arcuate fixation
member illustrated in Figures 1 A and 1 B;
[0020] Figure 4G is a top elevation view of the arcuate fixation member
illustrated in
Figure 4F, without the arcuate fixation member illustrated in Figures IA and
1B;
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[0021] Figure 5 is a cranial-caudal view of a vertebral body with the arcuate
fixation
member illustrated in Figure 4C inserted therein;
[0022] Figure 6 is a cranial-caudal view of a vertebral body with the arcuate
fixation
member illustrated in Figures 4F inserted therein;
[0023] Figure 7 is a posterior view of an example spinal fixation construct
utilizing
embodiments of the arcuate fixation members illustrated in Figure 4F; and
[0024] Figures 8A and 8B are side elevation views of an embodiment of an
arcuate
fixation member delivery instrument;
[0025] Figures 9A is a side elevation view of an arcuate fixation member
constructed in
accordance with another embodiment;
[0026] Figure 9B is a perspective view of the arcuate fixation member
illustrated in
Figure 9A;
[0027] Figure 9C is a top elevation view of an embodiment of an intervertebral
implant
for use with arcuate fixation members;
[0028] Figure 9D is a front elevation view of the intervertebral implant
illustrated in
Figure 9C;
[0029] Figure 9E is a side elevation view of the intervertebral implant
illustrated in
Figure 9C;
[0030] Figure 9F is a front elevation view of an embodiment of a fixation
plate for use
with the intervertebral implant illustrated in Figures 9C to 9E;
[0031] Figure 9G is a top elevation view of the fixation plate illustrated in
Figure 9F;
[0032] Figure 9H is a front elevation view of a blocking plate for use with
the fixation
plate illustrated in Figures 9F and 9G;
[0033] Figure 91 is a top elevation view of the blocking plate illustrated in
Figure 9H;
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[0034] Figure 9J is a side elevation view of a locking screw for use with the
fixation
plate illustrated in Figures 9F and 9G;
[0035] Figure 9K is an exploded view of an assembly utilizing the components
illustrated in Figures 9A to 9J;
[0036] Figure 9L is a perspective view of an assembly utilizing the components
illustrated in Figures 9A to 9J;
[0037] Figure 9M is a side elevation view of the assembly illustrated in
Figure 9L
inserted into an intervertebral space;
[0038] Figure I OA is a top elevation view of another embodiment of an
intervertebral
implant for use with arcuate fixation members;
[0039] Figure l OB is a front elevation view of the intervertebral implant
illustrated in
Figure 10A;
[0040] Figure IOC is a top elevation view of another embodiment of an
intervertebral
implant for use with arcuate fixation members;
[0041] Figure I OD is a front elevation view of the intervertebral implant
illustrated in
Figure IOC;
[0042] Figure I OE is a front elevation view of an embodiment of a fixation
plate for use
with the intervertebral implants illustrated in Figures 1 OA to l OD;
[0043] Figure I OF is a top elevation view of the fixation plate illustrated
in Figure 10E;
[0044] Figure l OG is a front elevation view of a blocking plate for use with
the fixation
plate illustrated in Figures 1 OE and I OF;
[0045] Figure I OH is a top elevation view of the blocking plate illustrated
in Figure
l OG;
[0046] Figure 101 is an exploded view of an assembly utilizing the components
illustrated in Figures 1 OA to l OH;
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[0047] Figure l OJ is a perspective view of an assembly utilizing the
components
illustrated in Figures 1 OA to l OH;
[0048] Figure 1 IA is a front elevation view of a ratchet plate for use with
the fixation
plate illustrated in Figures 1 OE and I OF;
[0049] Figure 1 lB is a top elevation view of the ratchet plate illustrated in
Figure 1 IA;
[0050] Figure 11 C is a side elevation view of the ratchet plate illustrated
if Figure 11 A;
[0051] Figures I 1D is a perspective view of an arcuate fixation member
constructed in
accordance with another embodiment;
[0052] Figure l lE is an exploded view of an assembly utilizing the components
illustrated in Figures 9J, 10E, IOF, and 1 IA to 11D;
[0053] Figure 11F is a perspective view of the assembly illustrated in Figure
1 1E;
[0054] Figures 11G and 11H illustrate a side elevation cross sectional view of
the
assembly illustrated in Figure 1 IE;
[0055] Figure 12A is a perspective view of an arcuate fixation member and a
complimentary screw constructed in accordance with another embodiment;
[0056] Figure 12B is a perspective view of the arcuate fixation member and the
complimentary screw in a mated configuration;
[0057] Figure 12C is a perspective view of an arcuate groove configured to
receive the
components illustrated in Figures 12A and 12B;
[0058] Figure 12D is a perspective view of an assembly utilizing the
components
illustrated in Figures 12A to 12C;
[0059] Figure 13A is an exploded view of an assembled components of an
embodiment
of a delivery instrument;
[0060] Figure 13B is a perspective view of an embodiment of a guide ring for
use with
the components illustrated in Figure 13A;
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[0061] Figure 13C is a perspective view of an embodiment of a drive head for
use with
the components illustrated in Figure 13A
[0062] Figure 13D is a side elevation view of an assembly utilizing components
illustrated in Figures 13A to 13C in combination with the assembly illustrated
in Figure 9L;
[0063] Figure 13E is a perspective view of the assembly illustrated in Figure
13D;
[0064] Figure 13F is a perspective view of another embodiment of the delivery
instrument illustrated in Figures 13A to 13E;
[0065] Figure 14A is a top elevation view of assembled components of another
embodiment of a delivery instrument;
[0066] Figure 14B is a perspective view of a component illustrated in Figure
14A;
[0067] Figure 14C is a perspective view of another of the components
illustrated in
Figure 14A;
[0068] Figure 14D is a perspective view of components illustrated in Figure
14A; and
[0069] Figure 14E is a perspective view of another embodiment of the delivery
instrument illustrated in Figures 14A to 14D.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0070] Certain terminology is used in the following description for
convenience only
and is not limiting. The words "right", "left", "top" and "bottom" designate
directions in the
drawings to which reference is made. The words "inwardly" and "outwardly"
refer to directions
toward and away from, respectively, the geometric center of the device and
designated parts
thereof. The words, "anterior", "posterior", "superior", "inferior",
"lateral", "medial", "sagittal",
"axial", "coronal," "cranial," "caudal" and related words and/or phrases
designate preferred
positions and orientations in the human body to which reference is made and
are not meant to be
limiting.
[0071] The words "arcuate" and "curved" as used herein refer generally to the
varying
physical geometry of an object along an axis coincident to the object, for
example the deviation
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from straightness of the body of an arcuate fixation member along a central
longitudinal axis
defined with the body of the object between its proximal and distal ends.
Generally, with
reference to a straight axis projected from a first end of such an object, as
distance from the first
end of the object increases along the central longitudinal axis of the object,
distance between the
central longitudinal axis of the object and the straight axis increases more
or less continuously,
so that the body of the object defined along its central longitudinal axis
takes on a curved or
arcuate shape. The resulting curvature of the central longitudinal axis may
exhibit a constant or
uniform radius with respect to a point in space defined remotely from the body
of the object.
Alternatively, a non-uniform or varying radius of curvature may be defined.
The curvature of
the body of the object defined by the longitudinal axis may also vary in
direction with respect to
a Cartesian coordinate system. The curvature may be uniformly distributed
along the body of the
object, for example between the proximal and distal ends of the object, or may
be localized
within one or more distinct segments of the body of the object. The curvature
of the object may
be significantly smooth and continuous along its central longitudinal axis,
may be defined by a
series of straight interconnected segments where each successive segment
defines an increasing
angle between the central longitudinal axis of the body of the object and the
straight axis, or any
combination thereof.
[0072] The words "vertebral body" as used herein should be interpreted broadly
to
include all the bones and bony structures found within and in the immediate
proximity of the
human spinal system, including but not limited to those found in the cervical
region, the thoracic
region, the lumbar region, and the sacral curve region.
[0073] The terminology intended to be non-limiting includes the above-listed
words,
derivatives thereof and words of similar import.
[0074] Described herein are arcuate fixation members with varying
configurations
and/or features, along with additional components for use therewith in
fixation systems and
intervertebral implant systems. Applications of fixation systems and/or
intervertebral implants
systems utilizing arcuate fixation members could include, but are not limited
to, fixation of the
endplate components of a total disc replacement to vertebral bodies, lateral
mass fixation in the
cervical spine, direct fixation of an intervertebral implant to vertebral
bodies, fixation into
osteoporotic bone, anchor-in-anchor fixation into underlying bone, securing
auxilary fixation
devices to underlying bone, and the like. The use of systems and/or methods
utilizing arcuate
fixation members disclosed herein are particularly suitable when a linear line-
of-approach for
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delivering fixation member is undesirable. It should be noted that the
physical characteristics of
the arcuate fixation members disclosed herein may cause them to be alternately
described as
arcuate blades, arcuate pins, arcuate nails, or other terms of similar
descritptive import.
[0075] With initial reference to Figures IA to 1H, an example embodiment of a
fixation
system 10 comprising an arcuate fixation member 12A and a guiding member 14 is
illustrated.
As will become appreciated from the description below, one or more arcuate
fixation members
12A may be utilized, alone or in combination with one or more guiding members
14, to securely
fasten auxiliary fixation devices, for example fixation rods, to an underlying
bone, such as a
vertebral body. Unless otherwise indicated, the bone fixation system 10 and
its components can
be manufactured from any suitable biocompatible material known in the art
including but not
limited to titanium, titanium alloy such as TAN, stainless steel, reinforced
plastics, allograft
bone, and the like.
[0076] Figures IA and lB illustrate front and side views of the arcuate
fixation member
12A respectively. The arcuate fixation member 12A includes a body 16 defining
a proximal
endl6a and a distal end l6b opposite the proximal end. The distal end l6b may
comprise a tip
18 configured to cut into underlying structure or bone. The body 16 may
further define an
intermediate portion between the proximal end 16a and the distal end l6b that
is curved along a
central curved axis Ll. In an embodiment, the intermediate portion is curved
along substantially
the entire length of the body between the proximal end 16a and the distal end
16b, as depicted in
Figure I B. Alternatively, one or more distinct portions of the intermediate
portion between the
proximal end 16a and the distal end l6b may be curved (not shown). It should
be appreciated
that while the various embodiments of arcuate fixation members described and
illustrated in the
instant disclosure feature a uniform direction of curvature with respect to
the central curved axis
L1, arcuate fixation members in which the direction of curvature reverses
and/or otherwise
deviates within the intermediate portion are contemplated and meant to be
included within the
scope of the instant disclosure.
[0077] In an embodiment, the intermediate portion is curved along the central
curved
axis L1 in accordance with a uniform radius of curvature R1. Alternatively,
the intermediate
portion may define a non-uniform radius of curvature along the central curved
axis L1. In a
preferred embodiment, the curvature of the intermediate portion may be smooth
and continuous.
Alternatively, the curvature of the intermediate portion may be defined by a
series of
substantially straight sections (not shown), with each substantially straight
section aligned along
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an individual longitudinal axis corresponding to the individual section, where
the magnitude of
an angle a with respect to a perpendicular reference axis extended from the
proximal end 16a
increases in magnitude with the distance of each subsequent straight section
from the proximal
end 16a.
[0078] The body 16 of the arcuate fixation member 12A may define a variety of
cross
sectional geometries. In an embodiment, the body 16 may define a substantially
rectangular
cross section, defined by an inner surface 20, an outer surface 22
substantially parallel with and
opposite to the inner surface 20, and lateral surfaces 24 on opposite sides of
the body 16, as
depicted in Figure 1 C.. The lateral surfaces 24 may be substantially
perpendicular to the inner
and outer surfaces 20 and 22 respectively. In another embodiment, the body 16
may define a
substantially hexagonal cross section defined by an inner surface 20, an outer
surface 22
substantially parallel with and opposite to the inner surface 20, inner
chamfered surfaces 20a,
and outer chamfered surfaces 22a, as illustrated in Figure 1D. The inner and
outer chamfered
surfaces 20a and 22a respectively may converge to form lateral edges 26 on
opposite sides of the
body 16. The lateral edges 26 may be configured to cut into underlying
structure or bone. In yet
another embodiment, the body 16 may define a substantially elliptical cross
section, defined by
inner and outer surfaces 20 and 22 respectively, as illustrated in Figure 1E.
The inner and outer
surfaces 20 and 22 respectively may converge to form lateral edges 26 on
opposite sides of the
body 16. The lateral edges 26 may be configured to cut into underlying
structure or bone. In yet
another embodiment, the body 16 may define a round or elliptical cross section
with a
continuous outer surface lacking any edges (not shown). It should be noted
that the above-
discussed cross sectional geometries of the body 16 are merely examples, and
the scope of the
instant disclosure should not be limited thereto.
[0079] In an embodiment, the cross sectional area of the body 16 may remain
uniform
between the proximal end 16a and the distal end 16b. In another embodiment,
the cross sectional
area of the body 16 may diminish along the central curved axis L1 with
increasing distance
extending from the proximal end 16a (i.e., the body 16 may define a tapered
geometry between
the proximal 16a and the distal end l6b) toward the distal end 16b, resulting
in a cross sectional
area of the body 16 at the distal end l6b that is of a smaller magnitude than
the cross sectional
area of the body at the proximal end 16a. In an embodiment, the cross
sectional area of the body
16 in the area of the distal end l6b may be configured to form the tip 18 at
the distal end 16b.
For example, the tip 18 may be formed where the inner surface 20 and the outer
surface 22
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converge at the distal end 16b, such that a tip with a square geometry is
formed along a surface
substantially perpendicular to the lateral surfaces 24. In another embodiment,
a pointed tip (not
shown) may be formed at the distal end 16b, by defining a plurality of tip
surfaces that form
acute angles with the central curved axis L1 at the proximal end 16b. It
should be noted that
these tip geometries are merely examples, and the scope of the instant
disclosure should not be
limited thereto.
[0080] The arcuate fixation member 12A may be configured to slidably engage
with a
curved guiding bore 28 defined in the guiding member 14. In an embodiment, a
groove 30 may
be defined within a portion of the body 16 between the proximal end 16a and
the distal end 16b.
For example, the groove 30 may be formed on the inner surface 20 and/or the
outer surface 22.
Groove to engage guiding member. The groove 30 may be formed with a constant
width and/or
depth. Alternatively, the width and/or depth of the groove may diminish with
distance extending
from the proximal end 16a towards the distal end 16b, to introduce a
frictional engagement force
as the arcuate fixation member 12A is inserted into the curved guiding bore 28
of the guiding
member 14. The groove 30 may be formed in the body 16 using any geometry
appropriate for
achieving slidable engagement with the complimentary curved guiding bore 28.
For example,
Figure IF illustrates a cross sectional view of the body 16 with rectangular
grooves 30 formed in
the inner and outer surfaces 20 and 22 respectively, configured to slidably
engage with the "I"
shaped curved guiding bore 28 defined in the guiding member 14. It should be
noted that this
rectangular groove geometry is only an example, and the scope of the instant
disclosure should
not be limited thereto.
[0081] The arcuate fixation member 12A may have a head 32 defined at the
proximal
end 16a of the body 16. The head 32 may include a cylindrical body 34, or may
include any
other body geometry as appropriate. The head 32 may define a proximal end 32a
and a distal
end 32b. The distal end 32b of the head 32 may be coupled to the proximal end
16a of the body
16, either directly or indirectly via a neck 36 that is coupled between the
proximal end 16a of the
body 16 and the distal end 32b of the head 32. The cylindrical body 34 may
have external
surfaces 34a formed within opposing sides of the cylindrical body 34. The
external surfaces 34a
may be formed along vertical planes formed within the cylindrical body 34, the
vertical planes
being parallel with the central curved axis L1. The external surfaces 34a may
be further
configured to be engaged by complimentary features of a delivery instrument.
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[0082] The cylindrical body 34 may have a slot 38 formed therein along an axis
perpendicular to the central curved axis L1, the slot 38 defined by an open
end 38a and extending
from the proximal end 32a of the head 32, downward into the cylindrical body
34, the slot
terminating a seat end 38b. The seat end 38b of the slot 38 may be configured
to nestably
receive a component of a fixation system, for example a fixation rod (not
shown) and the like.
The slot 38 may further define two end cap surfaces 32c within the head 32 in
the area of the
proximal end 32a, on opposing sides of the slot 38. The end cap surfaces 32c
may be configured
with engaging features 32d for lockably engaging an end cap (not shown), for
example a pedicle
screw end cap, or the like. The engaging features may comprise a series of
threads or any other
features appropriate for lockably engaging an end cap.
[0083] In an example embodiment, the above-described components of the arcuate
fixation member 12A, including the body 16, the head 32, and the neck 36, may
all be coupled
together in a rigid assembled configuration prior to insertion. In another
example embodiment,
the arcuate fixation member 12A may comprise separate components that are
assembled in a
non-rigid configuration prior to insertion. For example, in the embodiment
illustrated in Figure
1 G, the body 16 of the arcuate fixation member 12A is coupled to the neck 36
at the proximal
end 16a of the body 16. A toggle head 40 may be coupled to the upper end of
the neck 36,
opposite the end where the neck 36 is coupled to the body 16. The toggle head
40 includes an
annular body that defines a proximal, or upper, end 40a, a distal, or lower,
end 40b, and a
radially outer surface 40c. The annular body of the toggle head 40 can define
the shape of a
segment of a sphere as illustrated, having a diameter or cross-sectional
dimension that is greater
at a location between the proximal and distal ends 40a and 40b than at either
of the proximal and
distal ends 40a and 40b. Accordingly, the radially outer surface 40c can be
spherical or
otherwise convex. Of course, the toggle head 40 can assume any other suitable
alternative shape
as desired. A series of annular rings 40d may be defined within the radially
outer surface 40c
between the proximal and distal ends 40a and 40b. The annular rings 40d may be
configured to
engage a complementary inner annular ring 32f formed in the area of an
aperture 32e defined
within the distal end 32b of the head 32. The geometry of the aperture 32e may
be configured to
allow the body 16 and neck 36 of the arcuate fixation member 12A to be
inserted into the head
32 and through the distal end 32b of the head 32, such that the outer surface
40c of the toggle
head 40 becomes seated within the aperture 32e in an assembled configuration.
In an assembled
configuration, the head 32 may rotate and/or translate about the toggle head
40 prior to final
tightening of the assembled configuration, providing additional freedom of
alignment, for
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example when the arcuate fixation member 12A is used in spinal fixation
constructs. When the
assembled configuration undergoes final tightening, one or more of the annular
rings 40d of the
outer surface 40c of the toggle head 40 may lockably engage with the inner
annular ring 32f of
the head 32, thereby locking the head 32 into position with respect to the
toggle head 40.
[0084] Now referring to Figure 1H, the guiding member 14 may include a
cylindrical
body 42, or may include any other body geometry as appropriate. The guiding
member 14 may
define a proximal end 14a, a distal end 14b, and an outer surface 14c having
threads defined
thereon. The threads defined on the outer surface 14c may be configured to cut
into underlying
structure or bone. A curved guiding bore 28 may be formed through the body 42
between the
proximal end 14a and the distal end 14b. The geometry of the curved guiding
bore 28 may be
configured in such a way as to slidably engage with a complimentary cross
sectional geometry of
the body 16 of the arcuate fixation member 12A. The curved guiding bore 28 may
be defined by
a constant cross sectional geometry between the proximal end 14a and the
distal end 14b.
Alternatively, the cross sectional geometry of the curved guiding bore 28 may
diminish in
magnitude with distance extending from the proximal end 14a downward in the
direction of the
distal end 14b, to introduce a frictional engagement force as the arcuate
fixation member 12A is
received within the curved guiding bore 28. The curved guiding bore 28 is
depicted with an "I"
shaped geometry in Figure 1H, but this curved guiding bore geometry is only an
example, and
the scope of the instant disclosure should not be limited thereto.
[0085] Now referring to Figures 2 and 3, the fixation system 10 is illustrated
with a pair
of the arcuate fixation members 12A and the guiding members 14 in an example
embodiment of
an assembled configuration within a vertebral body V1. In one method of
assembling the
fixation system 10, a guiding member 14 is driven into the vertebral body V1
so that the threads
of the outer surface 14c engage the bone of the vertebral body V1. A guide
hole with a diameter
of lesser magnitude than the outer diameter of the helical threads of the
guiding member 14 may
be bored in the vertebral body V1 before the guiding member 14 is driven into
the vertebral
body. The guiding member 14 may be driven into the vertebral body to a
sufficient depth so that
the surface of the proximal end 14a of the guiding member is substantially
flush with the outer
surface of the vertebral body V1. Once the guiding member 14 is sufficiently
anchored within
the vertebral body V1, an arcuate fixation member 12A may be slid into the
curved guiding bore
28 of the guiding member 14 in preparation for driving the arcuate fixation
member 12A into the
bone of the vertebral body V1. Once inserted into driving position within the
guiding member
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14, the arcuate fixation member 12A may be driven into the bone of the
vertebral body V1 via a
biasing force. In an embodiment, biasing force may be applied by a delivery
instrument as
described in greater detail below. The assembled pair of the arcuate fixation
members 12A and
the guiding members 14, as illustrated in Figures 2 and 3, may comprise the
first tier of a
bilateral spinal fixation construct. It should be noted that utilization of
the fixation system 10 in
a sacrum (i.e., the vertebral body V 1) as illustrated in Figures 2 and 3 is
merely an example, and
that the fixation system 10 may be utilized in any other type of vertebral
body, or other bony
structure, as appropriate. It should further be noted that while the fixation
system 10 has been
described thus far to include both the arcuate fixation member 12A and the
guiding member 14
to guide the arcuate fixation member 12A as it inserted into bone, alternative
embodiments of
constructing the fixation system 10 may omit the use of the guiding member 14,
whereby the
guiding function performed by the guiding member 14 may be performed by a
delivery
instrument.
[0086] Now referring to Figures 4A to 4E, in another example embodiment of the
spinal fixation system 10, an arcuate fixation member 12B is illustrated. It
should be noted
preliminarily that in the interest of brevity, the figures and subsequent
description pertaining to
the arcuate fixation member 12B do not refer to certain features of the
arcuate fixation member
12A that may be integrated into the arcuate fixation member 12B, for example
the groove 30
within the body 16, or the use of the arcuate fixation member 12A in
combination with the
guiding member 14 in an assembled configuration. However, embodiments in which
those and
other features of the arcuate fixation member 12A are integrated into the
arcuate fixation
member 12B are intended to be within the scope of the instant disclosure.
[0087] The arcuate fixation member 12B may have a lateral tab 44 defined at
the
proximal end 16a of the body 16, the lateral tab defining a proximal end 44a
and a distal end 44b
opposite the proximal end. The lateral tab 44 includes a tab body 46 that is
coupled to the body
16 of the arcuate fixation member 12B at the proximal end 44a and extends
outwardly from the
body 16 toward the distal end 44b. The tab body 46 may be defined by an upper
surface 46a, a
lower surface 46b, and a lateral surface 46c defined between the upper and
lower surfaces 46a
46b and extending around the tab body 46. The tab body 46 may be formed so
that the upper
and lower surfaces 46a and 46b are substantially coplanar with a plane defined
perpendicular to
the central curved axis L1 at the proximal end 16a of the body 16.
Alternatively, tab body 46
may be formed so that the upper and lower surfaces 46a and 46b define planes
that form at least
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one acute angle with respect to a plane defined perpendicular to the central
curved axis L1 at the
proximal end 16a of the body 16. Forming the tab body 46 at varying angles
with respect to a
plane defined perpendicular to the central curved axis L1 at the proximal end
16a of the body 16
allows the geometry of the tab body 46 with respect to the body 16 to be
conformed to varying
patient anatomies. Example embodiments with angled tab bodies 46 are
illustrated in Figures 4D
and 4E. The lower surface 46b of the tab body 46 may have gripping features
defined therein
configured to grip bone, for example serrated teeth (not shown) or the like.
Such gripping
features may provide stability against rotational forces when the arcuate
fixation member is
inserted into bone in an assembled configuration.
[0088] The tab body 46 may have an aperture 48 formed therethrough. In an
example
embodiment, the aperture 48 may define a through hole with a radius R1
extending from a
longitudinal axis L2. An inner surface 48a of the aperture 48 may be threaded
to receive
complimentary threads of a fixation anchor 50, for example a pedicle screw, or
the like. The
fixation anchor 50 includes a shaft 52 that extends longitudinally along a
longitudinal shaft axis
S 1. The shaft 52 defines longitudinally opposing proximal, or upper, and
distal, or lower, ends
52a and 52b, respectively, and a head 54 coupled to the proximal end 52a. It
should be noted
that the head 54 of fixation anchor 50 may be configured with similar features
to those described
above with respect to head 32 of the arcuate fixation member 12B. Helical
threads 56 extend
radially out from the shaft 52 at locations at and between the proximal and
distal ends 52a and
52b that are configured to engage underlying structure or bone. Thus, a
substantial entirety of
the shaft 52 between the proximal and distal ends 52a and 52b may be threaded.
A distal end
54a of the head 54 is coupled to the proximal end 52a of the shaft 56, either
directly or indirectly
via an unthreaded neck 58 that is coupled between the proximal end 52a of the
shaft 52 and the
distal end 54a of the head 54.
[0089] A portion 60 of the shaft 52 between a distal end 58a of the neck 58
and the
proximal end 52a of the shaft 52 may have engagement features defined thereon
configured to
lockingly engage with complimentary engagement features formed within the
inner surface 48a
of the aperture 48. For example, helical locking threads 60a may extend
radially out from the
portion 60 of the shaft 52 at locations at and between the distal end 58a of
the neck 58 and the
proximal end 52a of the shaft 52 that are configured to engage the
complimentary threads formed
within the inner surface 48a of the aperture 48. In an example embodiment, the
helical locking
threads 60a may define an outer diameter that decreases in a direction from
the distal end 58a of
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the neck 58 toward the proximal end 52a of the shaft 52. Accordingly, the
helical locking
threads 60a disposed at the distal end 58a of the neck 58 may define an outer
diameter that is
greater than the outer diameter of the helical locking threads 60a disposed at
the proximal end
52a of the shaft 52, as illustrated in Figure 4C. Alternatively, the outer
diameter of the helical
locking threads 60a may remain constant between the distal end 58a of the neck
58 toward the
proximal end 52a of the shaft 52.
[0090] Now referring to Figures 4F and 4G, in another example embodiment of
the
spinal fixation system 10, the tab body 46 of the arcuate fixation member 12B
may have a curved
guiding bore 62 formed therethrough along a central curved axis L3 that forms
an angle R with
the central curved axis L1. The geometry of the curved guiding bore 62 may be
configured in
such a way as to slidably engage with a complimentary cross sectional geometry
of the body 16
of the arcuate fixation member 12A. By varying the angle R between the central
curved axes L1
and L3, and thus rotating the configuration of the curved guiding bore 62
within the tab body 46
about the central curved axis L3, it is possible to conform how the bodies 16
of the arcuate
fixation members 12A and 12B will be positioned in an assembled configuration
(e.g., as
illustrated in Figure 4F) for varying patient anatomies. The curved guiding
bore 62 may be
defined by a constant cross sectional geometry between the upper and lower
surfaces 46a and
46b of the tab body 46. Alternatively, the cross sectional geometry of the
curved guiding bore
62 may diminish in magnitude with distance extending from the upper surface
46a downward in
the direction of the lower surface 46b, to introduce a frictional engagement
force as the arcuate
fixation member 12A is received within the curved guiding bore 62. The curved
guiding bore 62
is depicted with an "I" shaped geometry in Figure 4G, but this curved guiding
bore geometry is
only an example, and the scope of the instant disclosure should not be limited
thereto.
[0091] Now referring to Figures 5 to 7, example embodiments of the fixation
system 10
incorporating various embodiments of the arcuate fixation member 12B are
illustrated. In Figure
5, an arcuate fixation member 12B with the aperture 48 formed within the tab
body 46 has been
inserted into a vertebral body V2. As depicted, the arcuate fixation member
12B has been
inserted such that the lower surface 46b of the tab body 46 is engaged with
the outer bone
surface of the vertebral body V2. In an alternative embodiment, a recess (not
shown) may be
formed, for example by a boring instrument, within the outer bone surface of
the vertebral body
V2, the geometry of the recess configured to the receive the tab body 46 such
that the upper
surface 46a of the tab body 46 is substantially flush with the outer bone
surface of the vertebral
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body V2 when the arcuate fixation member 12B is fully inserted into the
vertebral body V2.
Once the arcuate fixation member 12B is in a fully inserted position within
the vertebral body
V2, a fixation anchor 50 may be inserted into the aperture 48 of the tab body
46 and driven into
to the underlying bone of the vertebral body V2. The fixation anchor 50 may be
driven into the
underlying bone of the vertebral body V2 until distal end 54a of the head 54
is flush against the
upper surface 46a of the tab body 46 in an assembled configuration.
[0092] In the fully assembled configuration of Figure 5, the arcuate fixation
member
12B and the fixation anchor 50 form a stable triangular load bearing plane
defined by the central
curved axis L1 and the longitudinal shaft axis Si, and a direction extending
between the body 16
of the arcuate fixation member 12B and the shaft 52 of the fixation anchor 50
(for instance,
between the distal ends l 6b and 52b of the arcuate fixation member 12B and
the fixation anchor
50 respectively). This triangular load bearing plane provides additional
structural integrity and
enhanced resistance to pullout forces than typical fixation systems employing
fixation members
deployed along parallel longitudinal axes. Additionally, because the body 16
of the arcuate
fixation member 12B and the shaft 52 of the fixation anchor 50 are angled with
respect to each
other, each of these anchors resists migration within the bone due, for
instance, to longitudinal
forces applied to the other bone anchor, that would tend to pull the bone
anchor out of the
underlying bone.
[0093] In Figure 6, as in Figure 5, an arcuate fixation member 12B with the
curved
guiding bore 62 formed within the tab body 46 has been inserted into the
vertebral body V2. As
depicted, the arcuate fixation member 12B has been inserted such that the
lower surface 46b of
the tab body 46 is engaged with the outer bone surface of the vertebral body
V2. In an
alternative embodiment, a recess (not shown) may be formed, for example by a
boring
instrument, within the outer bone surface of the vertebral body V2, the
geometry of the recess
configured to the receive the tab body 46 such that the upper surface 46a of
the tab body 46 is
substantially flush with the outer bone surface of the vertebral body V2 when
the arcuate fixation
member 12B is fully inserted into the vertebral body V2. Once the arcuate
fixation member 12B
is in a fully inserted position within the vertebral body V2, an arcuate
fixation member 12A may
be inserted into the curved guiding bore 62 of the tab body 46 and driven into
to the underlying
bone of the vertebral body V2. The arcuate fixation member 12A may be driven
into the
underlying bone of the vertebral body V2 until the distal end 32b of the head
32 is flush against
the upper surface 46a of the tab body 46 in an assembled configuration.
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[0094] In the fully assembled configuration of Figure 6, the arcuate fixation
member
12B and the arcuate fixation member 12A form a stable triangular load bearing
plane defined by
the central curved axis L1 and the central curved axis L3, and a direction
extending between the
bodies 16 of the arcuate fixation members 12B and 12A (for instance, between
the distal ends
l6b of the arcuate fixation members 12B and 12A respectively). This triangular
load bearing
plane provides additional structural integrity and enhanced resistance to
pullout forces than
typical fixation systems employing fixation members deployed along parallel
longitudinal axes.
Additionally, because the bodies 16 of the arcuate fixation members 12B and
12A are angled
with respect to each other, each of these anchors resists migration within the
bone due, for
instance, to longitudinal forces applied to the other bone anchor, that would
tend to pull the bone
anchor out of the underlying bone.
[0095] In Figure 7, an example embodiment of the spinal fixation system 10
used in a
unilateral spinal fixation construct is illustrated. Three arcuate fixation
members 12B with the
curved guiding bores 62 formed within the tab bodies 46 have been driven into
the bone of three
adjacent vertebral bodies V3, V4, and V5. Three arcuate fixation members 12A
have been
inserted into the corresponding guiding bores of the three arcuate fixation
members 12B and
driven into the bone of the vertebral bodies V3, V4, and V5. Each assembled
combination of
arcuate fixation members 12B and 12A may be configured with a different angle
R between the
central curved axes L1 and L3, for example to conform to the individual
anatomy of each of the
vertebral bodies V3, V4, and V5. A spinal fixation rod 64 has been seated in
the grooves 38
formed within the heads 32 of the arcuate fixation members 12A, and the
fixation rod has been
secured in place within each of the grooves 38 using appropriate pedicle screw
caps, thereby
fixing the unilateral spinal fixation construct in an assembled configuration.
Each assembled
combination of the arcuate fixation members 12B and 12A form one of the above-
discussed
triangular load bearing planes between the bodies 16 of the arcuate fixation
members 12B and
12A in a respective one of the vertebral bodies V3, V4, and V5. The increased
torsional and/or
rotational rigidty characteristics exhibited by the fixation system 10 in this
configuration when
compared with typical pedicle screw spinal constructs make the fixation system
10 desirable for
use in unilateral spinal fixation procedures. It should be noted that although
Figure 7 illustrates a
unilateral spinal fixation construct using the arcuate fixation members 12B
and 12A of the spinal
fixation system 10, alternate example embodiments using one or more additional
components of
the spinal fixation system 10, for example including the use of one or more
fixation anchors 50
in lieu of one or more of the arcuate fixation members 12A, including the use
of one or more
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guiding members 14 in combination with one or more arcuate fixation members
12A, or any
combination thereof, are possible and intended to be included within the scope
of the instant
disclosure.
[0096] Now referring to Figures 8A and 8B, example embodiments of a delivery
instrument 66 for use in inserting the arcuate fixation members 12A and/or 12B
of the fixation
system 10 into underlying structure or bone are illustrated. The delivery
instrument 66 includes
a hollow guide shaft 68 with a proximal end 68a and a distal end 68b opposite
the proximal end.
The guide shaft 68 may have a key 68c formed therein between the proximal and
distal ends 68a
and 68b. The geometry of the key 68c may be defined to allow an arcuate
fixation member, for
example the arcuate fixation member 12B, to pass laterally through the key 68c
as it is being
driven into underlying structure or bone. The distal end 68d of the guide
shaft 68 may define
engaging features 68e, for example serrated teeth, configured to engage
underlying surface or
bone when the delivery instrument 66 is positioned for insertion of the
arcuate fixation members
12A and/or 12B.
[0097] In an example embodiment, a removable end cap 70 may be releasably
affixed to
the distal end 68a of the guide shaft 68. The end cap 70 may define an inner
rim surface 70a
with engagement features (e.g., threads) defined therein configured to
releasably engage with
complimentary engagement features formed at the distal end 68a of the guide
shaft 68.
Alternatively, the guide shaft 68 may include a solid end (not shown) formed
in a plane
perpendicular to the distal end 68a of the guide shaft 68. In example
embodiments, the end cap
70 or the solid end may have an optional collar 72 coupled therein configured
to receive a drive
shaft 74 having a longitudinal axis S2, a proximal end 74a, and a distal end
74b opposite the
proximal end. The collar may be configured to freely allow translation and/or
rotation of the
drive shaft 74, or may limit advancement and/or retraction of the drive shaft
74, for example by
complimentary threads formed within the collar 72 and on the drive shaft,
ratcheting features on
the drive shaft, or the like. In alternative embodiments where collar 72 is
omitted, the end cap 70
or the solid end may be configured to freely allow translation and/or rotation
of the drive shaft
74, or may limit advancement and/or retraction of the drive shaft 74, for
example by
complimentary threads formed within the collar 72 and on the drive shaft,
ratcheting features on
the drive shaft, or the like.
[0098] The proximal end 74a of the drive shaft 74 may be coupled, above the
end cap
70 or the solid end, to an actuator 76. The actuator may be configured to
impart rotational and/or
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translational forces to the drive shaft 74. The actuator may have gripping
features 76a defined
thereon configured to allow for easier application of a rotational force to
the actuator 76. In an
example embodiment, the gripping features 76a may include features designed to
enhance the
hand grip of an operator, for example a series of vertical ribs, knurls, or
the like. Alternatively,
the gripping features 76a may be configured to engage complimentary features
of a motorized
driving instrument such as a drill. An upper surface 76b of the actuator 76
may be configured to
receive an impaction force from a complimentary impaction instrument, for
example a hammer,
a mallet, a sonic hammer, a mechanical hammer, or the like.
[0099] An engaging head 78 may be coupled to the distal end 74b of the drive
shaft 74.
The engaging head 80 includes a body 80 defining an outer surface 80a. The
outer surface 80a
of the body 80 may have engaging features 80b defined therein configured to
matably engage
with complimentary engaging features l6c defined between the proximal end 16a
and the distal
end l6b of the body 16 of the arcuate fixation member 12B. In an example
embodiment, the
complimentary engaging features 80b and l6c are complimentary threads. In
another
embodiment, the engaging head 80 includes a gripping mechanism (not shown)
configured to
releasably engage the engaging features l6c of the of the body 16 of the
arcuate fixation member
12A and/or 12B. The gripping features of the engaging head 80 may be
controllable via the
actuator 76.
[0100] An optional cutting shaft (not shown) maybe configured to be received
within
the collar 72 or the solid end, the cutting shaft having a proximal end that
may be coupled, above
the end cap 70 or the solid end, to the actuator 76, and a distal end opposite
the proximal end, the
distal end having a cutting tool coupled thereto, the cutting tool configured
to cut an initial
pathway into the underlying structure, the initial pathway being of similar
cross sectional
geometry but proportionately smaller cross sectional area of an arcuate
fixation member 12A or
12B that is to be driven into the initial pathway and the underlying
structure. The cutting shaft
may be configured similarly to and advanced and/or retracted within the guide
shaft 68 similarly
to the drive shaft 74.
[0101] In an example method of using rotational insertion via the delivery
instrument 66
to insert an arcuate fixation member 12B, the arcuate fixation member 12B is
inserted through
the key 68c of the guide shaft 68 until the engaging features l6c at the
distal end l6b of the body
become matably engaged with the engaging features 80b of the body 80 of the
engaging head 78.
When assembled in this pre-insertion configuration, the central curved axis L1
will be
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substantially coincident with the longitudinal axis S2 of the drive shaft 74,
and the tip 18 of the
arcuate fixation member 12B will in a position slightly above and
substantially perpendicular to
an outer surface 82a of an underlying structure 82 (e.g., bone) into which the
arcuate fixation
member 12B is to be driven. The delivery instrument 66 may then be maneuvered
into position
within the patient such that the engaging features 68e of the guide shaft 68
engage with the outer
surface 82a of the underlying structure 82, and the tip 18 of the arcuate
fixation member 12B is
positioned above the desired insertion point for the arcuate fixation member
12B. The threads of
the complimentary engaging features 80b and l6c may be configured so that as a
rotational force
about the longitudinal axis S2 is imparted to the actuator 76, the engaging
head 80 applies a
downward biasing force to the tip 18 and the body 16 of the arcuate fixation
member 12B,
causing the arcuate fixation member 12B to be driven through the outer surface
82a and into the
underlying structure 82 along the longitudinal axis L1. The rotational force
may be imparted to
the actuator 76 by hand via an operator of the delivery instrument 66, via
rotational force from a
motorized source, or any combination thereof.
[0102] In an example method of using a combination of rotational and
impactional
insertion via the delivery instrument 66 to insert an arcuate fixation member
12B, the arcuate
fixation member 12B is inserted through the key 68c of the guide shaft 68
until the engaging
features l6c at the distal end l6b of the body become matably engaged with the
engaging
features 80b of the body 80 of the engaging head 78. When assembled in this
pre-insertion
configuration, the central curved axis L1 will be substantially coincident
with the longitudinal
axis S2 of the drive shaft 74, and the tip 18 of the arcuate fixation member
12B will in a position
slightly above and substantially perpendicular to an outer surface 82a of an
underlying structure
82 (e.g., bone) into which the arcuate fixation member 12B is to be driven.
The delivery
instrument 66 may then be maneuvered into position within the patient such
that the engaging
features 68e of the guide shaft 68 engage with the outer surface 82a of the
underlying structure
82, and the tip 18 of the arcuate fixation member 12B is positioned above the
desired insertion
point for the arcuate fixation member 12B.
[0103] The threads of the complimentary engaging features 80b and l6c maybe
configured so that as a rotational force about the longitudinal axis S2 is
imparted to the actuator
76, the drive shaft 74 is biased in an upward direction along the longitudinal
axis Si, causing the
drive shaft 74 and the actuator 76 to be displaced within the guide shaft 68
in an upward
direction away from the outer surface 82a of the underlying structure 82,
while maintaining
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engagement of the complimentary engaging features 80b and 16c. An downward
impaction
force may then be imparted to the actuator 76, causing the actuator 76, the
drive shaft 74, and the
engaging head 80 to be biased in a downward direction toward the outer surface
82a of the
underlying structure 82. The downward biasing force applied to the engaging
head 80 is
imparted to the arcuate fixation member 12B via the complimentary engaging
features 80b and
16c, causing the tip 18 and the body 16 of the arcuate fixation member 12B to
be driven though
the outer surface 82a and into the underlying structure 82 along the
longitudinal axis Ll. The
arcuate fixation member 12B may be driven into a fully inserted position via a
successive series
of rotational and impactional forces imparted to the actuator, such that the
drive shaft 74 and
actuator 76 are initially displaced upward from a starting position via
rotation, then biased
downward via impaction until the actuator 76 returns to its starting position,
simultaneously
biasing the arcuate fixation member 12B into the underlying structure 82, then
biased upward via
rotation from the starting position again, and so on. The successive
rotational and/or impactional
forces may be imparted to the actuator 76 by hand via an operator of the
delivery instrument 66,
via rotational and/or impactional forces from a motorized source, or any
combination thereof. It
should be noted that while Figures 8A and 8B and the accompanying description
are concerned
primarily with insertion of the arcuate fixation member 12B, the same delivery
instrument 66
and methods of use therefore may be used to insert the arcuate fixation member
12A.
[0104] Referring now to Figures 9A to 9M, an example embodiment of an
intervertebral implant system 100 comprising an arcuate fixation member 12C,
an intervertebral
implant 108, a fixation plate 116, a blocking plate 132, and a locking screw
138 is illustrated. As
will become appreciated from the description below, one or more fixation
members 12C may be
utilized to securely anchor an assembled configuration of intervertebral
implant system 100
within an intervertebral space between adjacent vertebral bodies. Unless
otherwise indicated, the
intervertebral implant system 100 and its components can be manufactured from
any suitable
biocompatible material known in the art including but not limited to titanium,
titanium alloy such
as TAN, stainless steel, reinforced plastics, allograft bone, and the like.
[0105] The arcuate fixation member 12C includes a body 102 defining a proximal
end102a and a distal end 102b opposite the proximal end. The distal end 102b
may comprise a
tip 104 configured to cut into underlying structure or bone. The body 102 may
further define an
intermediate portion between the proximal end 102a and the distal end 102b
that is curved along
a central curved axis Ll. In an embodiment, the intermediate portion is curved
along
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substantially the entire length of the body 102 between the proximal end 102a
and the distal end
102b. Alternatively, one or more distinct portions of the intermediate portion
between the
proximal end 102a and the distal end 102b may be curved (not shown).
[0106] In an embodiment, the intermediate portion is curved along the central
curved
axis L1 in accordance with a uniform radius of curvature R1. Alternatively,
the intermediate
portion may define a non-uniform radius of curvature along the central curved
axis L1. In a
preferred embodiment, the curvature of the intermediate portion may be smooth
and continuous.
Alternatively, the curvature of the intermediate portion may be defined by a
series of
substantially straight sections (not shown), with each substantially straight
section aligned along
an individual longitudinal axis corresponding to the individual section, where
the magnitude of
an angle a with respect to a perpendicular reference axis extended from the
proximal end 102a
increases in magnitude with the distance of each subsequent straight section
from the proximal
end 102a.
[0107] The arcuate fixation member 12C may have a head 106 defined at the
proximal
end 102a of the body 102. The head 106 may extend radially outward from the
proximal end
102a of the body 102 in a direction perpendicular to the longitudinal axis Ll.
In an example
embodiment, the head 106 may extend from the body 102 in a direction generally
opposite from
the direction of curvature of the body 102, as depicted in Figures 9A and 9B.
In alternative
embodiments, the head 106 may extend from the body 102 in a direction
generally towards the
direction of curvature of the body 102. The head may define an upper surface
106a configured
for multi-angular engagement with a complementary surface of a delivery
instrument, and a
lower surface 106b opposite the upper surface and configured to engage another
component of
the intervertebral implant system 100, for example the fixation plate 116,
when the arcuate
fixation member 12C is in a fully inserted position.
[0108] The intervertebral implant 108 is defined by a posterior side 108a, an
anterior
side 108b opposite the posterior side, lateral sides 108c, an upper surface
108d, and a lower
surface 108e opposite the upper surface. In an example embodiment, a portion
of the posterior
side 108a between the lateral sides 108c may be curved inwardly in the
direction of the anterior
side 108b, defining a rounded, generally rectangular kidney-like footprint, as
depicted in Figure
9C. In an alternative embodiment, a portion of the posterior side 108a between
the lateral sides
108c may be curved outwardly in a direction away from the anterior side 108b
(not shown). In
another alternative embodiment, the posterior side 108a may be substantially
straight between
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the lateral sides 108c, defining a rounded, generally rectangular footprint
(not shown). The
intervertebral implant 108 may have a central bore 110 formed therethrough,
the shape of which
substantially conforms to the footprint of the intervertebral implant 108
(e.g., a rounded,
generally rectangular kidney-like footprint, or a rounded, generally
rectangular footprint,
depending upon the geometry of the posterior side 108a). The central bore 110
can be filled with
bone growth inducing substances to allow bony ingrowth and to assist in fusion
between the
intervertebral implant 108 and adjacent vertebral bodies.
[0109] In an example embodiment of the intervertebral implant 108, the upper
and
lower surfaces 108d and 108e may have gripping features 108h such as teeth,
spikes, or similar
structures, formed thereon and configured to facilitate gripping engagement
between the upper
and lower surfaces 108d and 108e and the end plates of adjacent vertebral
bodies. The teeth 112
may be pyramidal, saw toothed or other similar shapes. In alternative
embodiments of the
intervertebral implant 108, portions of and/or the entirety of the upper and
lower surfaces 108d
and 108e may be substantially smooth and devoid of any protrusions. Upper and
lower edges
108f and 108g, defined where the upper and lower surfaces 108d and 108e
intersect with the
posterior, anterior, and lateral sides 108a, 108b, and 108c respectively
around the outer perimeter
of the intervertebral implant 108, may be rounded (not shown). In an example
embodiment, the
upper and lower edges 108f and 108g may be rounded using a uniform radius of
curvature
around the perimeter of the implant. In an alternative embodiment, the upper
and lower edges
108f and 108g may be rounded using a non-uniform radius of curvature around
the perimeter of
the implant. In another alternative embodiment, the upper and lower edges 108f
and 108g along
the anterior side 108b may be rounded with a greater radius than the remainder
of the upper and
lower edges 108f and 108g, such that a bull nose outer surface (not shown) is
created on the
anterior side 108b of the implant. Rounding upper and lower edges 108f and
108g may facilitate
easier insertion of the intervertebral implant 108, for example by minimizing
required distraction
of the end plates of adjacent vertebral bodies.
[0110] In an example embodiment, the intervertebral implant 108 has a
generally
wedge-shaped side-view profile. As illustrated in Figure 9E, this wedge shape
is defined by a
gradual decrease in the height of the intervertebral implant 108 (as measured
between the upper
and lower surfaces 108d and 108e) extending between the posterior side 108a in
the direction of
the anterior side 108b. The intervertebral implant 108 has a generally
constant height between
lateral sides 108c. In alternative embodiments, the intervertebral implant 108
may have a
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gradual increase in height followed by a gradual decrease in height extending
from one lateral
side 108c to the other, and/or may have a generally constant height between
the posterior and
anterior sides 108a and 108b, or may have convex and/or concave upper and
lower surfaces 108d
and 108e, thereby defining a gradual increase in height followed by a gradual
decrease in height
extending from the posterior side 108a to the anterior side 108b and from one
lateral side 108c to
the other.
[0111] A plurality of grooves 112 maybe formed within the intervertebral
implant 108
where the upper and lower surfaces 108d and 108e intersect with the anterior
side 108b. The
grooves 112 may be concave and may be configured to align with arcuate grooves
128 of the
fixation plate 116 when the intervertebral implant 108 and the fixation plate
116 are in an
assembled configuration. In an example embodiment, the grooves 112 may be
substantially
smooth and devoid of any protrusions. Retaining grooves 114 may be formed
within the lateral
sides 108c of the intervertebral implant 108 between the upper and lower
surfaces 108d and
108e. The retaining grooves 114 may be configured to releasably engage
complementary
engaging ribs 120 of the fixation plate 116.
[0112] The fixation plate 116 is defined by a generally C-shaped, channel-like
body
118 that includes an anterior side 118a with upper and lower sides 118b and
118c opposite each
other, and lateral sides 118d extending from opposite sides of the anterior
side 118a in a
generally perpendicular direction from the anterior side 118a. The anterior,
upper, lower, and
lateral sides 118a, 118b, 118c, and 118d may form a generally channel-like
structure (in essence,
a cradle) which may be configured to receive the anterior side 108b and at
least a portion of the
lateral sides 108c in partial nested engagement. As such, the upper and lower
sides 108b and
108c may define gradual increases and/or decreases in height in a posterior
direction from the
anterior side 118a and/or between the lateral sides 108d, in order to
generally conform the
fixation plate 116 to the geometry of the intervertebral implant 108. The
lateral sides 118d may
have engaging ribs 120 formed thereon at the ends opposite the anterior side
118a, the engaging
ribs 120 configured to be releasably received within the retaining grooves 114
of the
intervertebral implant 108.
[0113] The anterior side 118a of the fixation plate 116 may have a pair of
apertures 122
formed therethrough configured to receive grasping features of a delivery
instrument. In an
example embodiment, the apertures 122 may be D-shaped, as illustrated in
Figure 9C. However
any other aperture shape may be defined as appropriate. The apertures 122 may
have a retaining
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rib 124 formed therein configured to engage with a complimentary grasping rib
of the delivery
instrument. The anterior side 118a of the fixation plate 116 may also have a
central bore 126
formed therethrough having an inner surface 126a with threads configured to
engage
complimentary threads of a locking screw 138. The anterior side 118a of the
fixation plate 116
may also have a concave recess 130 formed therein configured to receive a
complimentary
convex surface 134d of the blocking plate 132.
[0114] The anterior side 118a of the fixation plate 116 may also have a
plurality of
arcuate grooves 128 formed therethrough configured to slidably receive the
arcuate fixation
members 12C and to define an insertion trajectory for each of the arcuate
fixation members 12C.
In an example embodiment, the arcuate grooves 128 may have a generally uniform
cross
sectional geometry configured to closely conform to the cross sectional
geometry of the body
102 of the arcuate fixation member 12C between the head 106 and the distal end
102b. When an
arcuate fixation member 12C is in a fully inserted position within a
respective arcuate groove
128, the lower surface 106b of the head 106 will be engaged with the outer
surface of the
anterior side 118a of the fixation plate 116. Because the upper surface 106a
of the head 106 will
not be flush with the outer surface of the anterior side 118a of the fixation
plate 116 in this
configuration, it may be desirable to omit the blocking plate 132 and the
locking screw 138. In
an alternative embodiment, the arcuate grooves 128 have a recessed ledge
formed therein in the
area where the arcuate grooves 128 intersect with the outer surface of the
anterior side 118a of
the fixation plate 116, the recessed ledge being configured to receive the
lower surface 106b of
the head 106 when the arcuate fixation member 12C is in a fully inserted
position, such that the
upper surface 106a of the head 106 is substantially flush with the outer
surface of the anterior
side 118a of the fixation plate 116.
[0115] The arcuate grooves 128 maybe disposed about the central bore 126 in
any
desired configuration and may define any insertion trajectories as
appropriate. In the example
embodiment depicted in Figures 9C to 9J, the arcuate grooves 128 are formed in
opposing
quadrants around the central bore 126, with two arcuate grooves 128 located
near the upper side
118b and defining two generally cranial insertion trajectories, and two
arcuate grooves 128
located near the lower side 118c and defining two generally caudal insertion
trajectories. It
should be noted that this configuration of arcuate groove 128 locations and
arcuate fixation
member 12C insertion trajectories is merely an example, and the scope of the
instant disclosure
should not be limited thereto.
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[0116] The blocking plate 132 is defined by a generally disc-shaped body 134
with
planar upper and lower surfaces 134a and 134b, an anterior surface 134c, and a
posterior surface
134d. The upper and lower surfaces 134a and 134b and the height of the body
134 (as measured
between the upper and lower surfaces 134a and 134b) may be defined to match
the height (as
measured between the upper and lower surfaces 118b and 118c)of the anterior
side 118a of the
fixation plate 116 when the blocking plate 132 is in a fully assembled
configuration. The
anterior surface 134c of the body 134 may be generally planar, or may be
defined to match the
outer surface of the anterior side 118a of the fixation plate 116 when the
blocking plate 132 is in
a fully assembled configuration. The posterior surface 134d may be defined as
a convex surface
configured to engage with the concave recess 130 formed in the anterior side
118a of the fixation
plate 116 when the blocking plate 132 is in a fully assembled configuration.
The body 134 may
have an aperture 136 formed therethrough. In an example embodiment, the
diameter of the
aperture may be slightly larger than the diameter of the central bore 126 of
the fixation plate 116,
such that a locking screw 138 may be inserted into the aperture with no
interference
therebetween. In another embodiment, the diameter of the aperture 136 may be
substantially the
same as that of the central bore 126, and the inner surface of the aperture
may have threads
formed thereon, the threads configured to engage complimentary threads of the
locking screw
138. The aperture 136 may further be defined by a concave recess 136a formed
within the
anterior surface 134c, the concave recess 136a configured to receive the
convex head 142 of the
locking screw 138.
[0117] The locking screw 138 includes a shaft 140 that defines longitudinally
opposing
proximal and distal ends 140a and 140b, respectively, and a head 142 coupled
to the proximal
end 140a of the shaft 140, either directly or indirectly via an unthreaded
neck 144 that is coupled
between the proximal end 140a of the shaft 140 and the head 142. The head 142
can define a
generally convex shape between the interface of the head 142 and the neck 144
that extends
outward towards a proximal end 142a of the head 142. The convex shape of the
head may be
configured to engage the concave recess 136a of the blocking plate 132. Of
course, the head 142
can assume any other suitable alternative shape as appropriate. Helical
threads 146 extend
radially out from the shaft 140 at locations at and between the proximal and
distal ends 140a and
140b that are configured to engage complementary threads on the inner surface
126a of the
central bore 126 of the fixation plate 116. Thus, a substantial entirety of
the shaft 140 between
the proximal and distal ends 140a and 140b may be threaded. The distal end
142a of the head
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142 may have driving features 142b defined therein, designed to engage with
complementary
driving features of a delivery instrument.
[0118] Referring now to Figures 91 and 9J, an example embodiment of the
intervertebral implant system 100 in a nearly completely assembled
configuration is illustrated.
Figure 91 depicts the intervertebral implant system 100 partially assembled
outside of an
intervertebral space (the blocking plate and locking screw have been omitted
for simplicity).
The intervertebral implant 108 has been seated within the fixation plate 116
such that the
retaining ribs are seated with the retaining grooves on the lateral sides of
the intervertebral
implant 108. Four arcuate fixation members 12C have been inserted through
corresponding
arcuate grooves within the fixation plate 116, and have been driven to an
almost fully inserted
position. In a final assembled configuration, the arcuate fixation members 12C
would be driven
into their fully inserted position, the blocking plate would be received
within the concave recess
in the anterior side of the fixation plate, and the locking screw would be
driven into the central
bore of the fixation plate and finally tightened, thereby blocking the arcuate
fixation members
12C from backing out of the assembled intervertebral implant system 100.
[0119] Figure 9M depicts an example embodiment of the intervertebral implant
system
100 partially assembled inside of an intervertebral space between adjacent
vertebral bodies V6
and V7 (the blocking plate and locking screw have been omitted for
simplicity). As an initial
step, the intervertebral implant 108 has been prepared for insertion, for
example by being packed
a with bone growth inducing substance and or/having its outer surfaces
properly prepared, and
has been seated within the fixation plate 116 such the retaining ribs are
seated with the retaining
grooves on the lateral sides of the intervertebral implant 108. The
intervertebral implant 108 was
then inserted into the intervertebral space between the adjacent vertebral
bodies V6 and V7using
a delivery instrument that is described in greater detail below. The delivery
instrument was then
used to deliver the four arcuate fixation members 12C into the arcuate grooves
in the fixation
plate and drive them into an almost fully inserted position. During the final
steps of the
assembly process, the delivery instrument would be used to drive the arcuate
fixation members
12C into their fully inserted position, the blocking plate would be received
within the concave
recess in the anterior side of the fixation plate, and the locking screw would
be driven into the
central bore of the fixation plate and finally tightened, thereby blocking the
arcuate fixation
members 12C from backing out of the assembled intervertebral implant system
100.
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[0120] Referring now to Figures I OA to l OJ, another example embodiment of
the
intervertebral implant system 100 comprising an arcuate fixation member 12C,
an intervertebral
implant 148, a fixation plate 156, a blocking plate 180, and a locking screw
138 is illustrated.
[0121] The intervertebral implant 148 has a generally C-shaped footprint
defined by a
posterior side 148a, lateral sides 148b terminating in distal ends 148c
opposite the posterior side
148a, an upper surface 148d, and a lower surface 148e opposite the upper
surface. In an example
embodiment, a portion of the posterior side 148a between the lateral sides
148b may be curved
inwardly in a direction toward the distal ends 14c, as depicted in Figures 1
OA and I OB. In an
alternative embodiment, a portion of the posterior side 148a between the
lateral sides 148b may
be curved outwardly in a direction away from the distal ends 148c (not shown).
In another
alternative embodiment, the posterior side 148a may be substantially straight
between the lateral
sides 148b, as depicted in Figures I OC and I OD. The posterior side 148a and
lateral sides 148b
define an open central bore 150, the shape of which substantially conforms to
the footprint of the
intervertebral implant 148. The central bore 150 can be filled with bone
growth inducing
substances to allow bony ingrowth and to assist in fusion between the
intervertebral implant 148
and adjacent vertebral bodies.
[0122] In an example embodiment of the intervertebral implant 148, the upper
and
lower surfaces 148d and 148e may have gripping features such as teeth, spikes,
or similar
structures formed thereon and configured to facilitate gripping engagement
between the upper
and lower surfaces 148d and 148e and the end plates of adjacent vertebral
bodies. The teeth may
be pyramidal, saw toothed or other similar shapes. In alternative embodiments
of the
intervertebral implant 148, portions of and/or the entirety of the upper and
lower surfaces 148d
and 148e may be substantially smooth and devoid of any protrusions. Upper and
lower edges
148f and 148g, defined where the upper and lower surfaces 148d and 148e
intersect with the
posterior and lateral sides 148a and 148b respectively around the perimeter of
the intervertebral
implant 148, may be rounded (not shown). In an example embodiment, the upper
and lower
edges 148f and 148g may be rounded using a uniform radius of curvature around
the perimeter
of the implant. In an alternative embodiment, the upper and lower edges 148f
and 148g may be
rounded using a non-uniform radius of curvature around the perimeter of the
implant. Rounding
upper and lower edges 148f and 148g may facilitate easier insertion of the
intervertebral implant
148, for example by minimizing required distraction of the end plates of
adjacent vertebral
bodies.
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[0123] In an example embodiment, the intervertebral implant 148 has a
generally
wedge-shaped side-view profile. This wedge shape is defined by a gradual
increase in the height
of the intervertebral implant 148 (as measured between the upper and lower
surfaces 148d and
148e) extending outwardly in a direction away the posterior side 148a in the
direction of the
distal ends 148c. The intervertebral implant 148 has a generally constant
height between lateral
sides 148b. In alternative embodiments, the intervertebral implant 148 may
have a gradual
increase in height followed by a gradual decrease in height extending from one
lateral side 148b
to the other, and/or may have a generally constant height between the
posterior sides 148a and
the distal ends 148c, or may have convex and/or concave upper and lower
surfaces 148d and
148e, thereby defining a gradual increase in height followed by a gradual
decrease in height
extending from the posterior side 148a to the distal ends 148c and from one
lateral side 148b to
the other.
[0124] Retaining grooves 152 maybe formed within the distal ends 148c of the
intervertebral implant 148, for example in a vertical direction substantially
perpendicular to a
horizontal midplane defined between the upper and lower surfaces 148d and
148e. The retaining
grooves 152 may be configured to releasably engage complementary retaining
ribs 160 of the
fixation plate 156. The distal ends 148c may also have access grooves 154
formed therein
between the upper and lower surfaces 148d and 148e. The access grooves 154 may
be
configured to align with complimentary access grooves 162 and/or 164 of the
fixation plate 156,
thereby defining an access cavity 168 for an engaging member of a delivery
instrument when the
intervertebral implant 148 and the fixation plate 156 are in an assembled
configuration.
[0125] The fixation plate 156 is defined by a generally rectangular body 158
that
includes an anterior side 158a and lateral sides 158b extending therefrom, the
lateral sides 158b
configured to engage with the retaining grooves 152 of the intervertebral
implant 148. In an
example embodiment, the lateral sided 158b are generally J-shaped, extending
initially from
opposite sides of the anterior side 158a in a direction perpendicular to and
away from the anterior
side 158a, and through curved sections 158c before returning in a direction
perpendicular to and
towards the anterior side 158a and terminating in distal ends 158d. It should
be noted that this
configuration for lateral sides 158b is merely an example, and any other
geometry may be used
as appropriate. Upper and lower edges of the anterior side 158a, defined where
upper and lower
surfaces 158e and 158f of the anterior side intersect with an anterior surface
158g of the anterior
side, may be rounded (not shown). In an example embodiment, the upper and
lower edges 158e
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and 158f may be rounded using a uniform radius of curvature. In an alternative
embodiment, the
upper and lower edges 158e and 158f may be rounded using a non-uniform radius
of curvature.
Rounding upper and lower edges 158e and 158f may facilitate easier insertion
of the fixation
plate 156, for example by minimizing required distraction of the end plates of
adjacent vertebral
bodies.
[0126] The lateral sides 158b may have retaining ribs 160 formed thereon at
the distal
ends 158d, the retaining ribs 160 configured to be releasably received within
the retaining
grooves 152 of the intervertebral implant 158. Access grooves 162 and 164 may
be formed
within the retaining ribs 160 and the lateral sides 158b, in the area where
the lateral sides 158b
interface with the anterior side 158a, respectively. The access grooves 162
and 164 may be
configured to align with complimentary access grooves 154 of the
intervertebral implant 148,
thereby defining an access cavity 168 for receiving an engaging feature of a
delivery instrument
when the intervertebral implant 148 and the fixation plate 156 are in an
assembled configuration.
The access grooves 164 may have a retaining shelf 166 formed therein
configured to engage with
an engaging feature of a delivery instrument, for example the raised ribs 258d
formed on the
insertion rods 258 of the delivery instrument 278, described in greater detail
below. The lateral
sides 158b may also have bores 178 formed within the curved sections 158c, the
apertures
configured to receive, for example the distal engagement tips 258c of the
insertion rods of 258 of
the delivery instrument 278.
[0127] The anterior side 158a of the fixation plate 156 may have gripping
grooves 168
formed within the upper and lower surfaces 158e and 158f of the anterior side
158a, the gripping
grooves 168 configured to receive grasping arms of a delivery instrument. The
gripping grooves
168 may have a gripping ridge 170 formed therein, the gripping ridge
configured to be engaged
by the complimentary grasping features formed at the ends of the grasping arms
of the delivery
instrument. The anterior side 158a of the fixation plate 156 may also have a
recess 172 formed
therein configured to receive additional components of the intervertebral
implant system 100, for
example a ratchet blade 188, a blocking plate 180, or the like. The anterior
side 158a may also
have a central bore 174 formed therethrough having an inner surface 174a with
threads
configured to engage complimentary threads of a locking screw 138. In an
example
embodiment, the central bore 174 may be formed within the recess 172.
[0128] The anterior side 158a of the fixation plate 156 may also have a
plurality of
arcuate grooves 176 formed therethrough configured to slidably receive the
arcuate fixation
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members 12C and to define an insertion trajectory for each of the arcuate
fixation members 12C.
In an example embodiment, the arcuate grooves 176 may have a generally uniform
cross
sectional geometry configured to closely conform to the cross sectional
geometry of the body
102 of the arcuate fixation member 12C between the head 106 and the distal end
102b. When an
arcuate fixation member 12C is in a fully inserted position within a
respective arcuate groove
176, the lower surface 106b of the head 106 will be engaged with the outer
surface of the
anterior side 158a of the fixation plate 156. Because the upper surface 106a
of the head 106 will
not be flush with the outer surface of the anterior side 158a of the fixation
plate 156 in this
configuration, it may be desirable to omit the blocking plate 180 and the
locking screw 138. In
an alternative embodiment, the arcuate grooves 176 have a recessed ledge
formed therein in the
area where the arcuate grooves 176 intersect with the outer surface of the
anterior side 158a of
the fixation plate 156, the recessed ledge being configured to receive the
lower surface 106b of
the head 106 when the arcuate fixation member 12C is in a fully inserted
position, such that the
upper surface 106a of the head 106 is substantially flush with the outer
surface of the anterior
side 158a of the fixation plate 156.
[0129] The arcuate grooves 176 maybe disposed about the central bore 174 in
any
desired configuration and may define any insertion trajectories as
appropriate. In the example
embodiment depicted in Figures 10E, l OF, 101 and l OJ, the arcuate grooves
176 are formed in
opposing quadrants around the central bore 174, with two arcuate grooves 176
located near the
upper surface 158e and defining two generally cranial insertion trajectories,
and two arcuate
grooves 176 located near the lower surface 158f and defining two generally
caudal insertion
trajectories. It should be noted that this configuration of arcuate groove 176
locations and
arcuate fixation member 12C insertion trajectories is merely an example, and
the scope of the
instant disclosure should not be limited thereto.
[0130] The blocking plate 180 is defined by a generally rectangular body 182
with an
anterior surface 182a, and a plurality of angled posterior surfaces 182b
generally opposite the
anterior surface 182a. The body 182 may have an aperture 186 formed
therethrough In an
example embodiment, the diameter of the aperture may be slightly larger than
the diameter of the
central bore 174 of the fixation plate 156, such that a locking screw 138 may
be inserted into the
aperture with no interference therebetween. In another embodiment, the
diameter of the aperture
186 may be substantially the same as that of the central bore 174, and the
inner surface of the
aperture may have threads formed thereon, the threads configured to engage
complimentary
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threads of the locking screw 138. The aperture 186 may further be defined by a
concave recess
186a formed within the anterior surface 182a, the concave recess 186a
configured to receive the
convex head 142 of the locking screw 138. The height, width, and depth of the
body 182 may be
proportioned so that the blocking plate 180 will be received within the recess
172 of the fixation
plate 156, such that the anterior surface 182a of the body 182 is
substantially flush with the
anterior surface 158g of the anterior side 158a of the fixation plate 156 when
the fixation plate
156 and the blocking plate 180 are in an assembled configuration. The anterior
surface 182a of
the body 182 may be generally planar, or may be defined to match the outer
surface of the
anterior side 158a of the fixation plate 156 when the blocking plate 180 and
the fixation plate
156 are in a fully assembled configuration.
[0131] In an example embodiment wherein the blocking plate 180 and locking
screw
138 are installed after the intervertebral implant 148 and fixation plate 156
have been inserted
into an intervertebral space and the arcuate fixation members 12C driven into
their fully inserted
positions, the angled posterior surfaces 182b and chamfered corners 184 of the
blocking plate
180 may be configured to engage the heads 106 of the arcuate fixation members
12C within the
recess 172 of the fixation plate 156 when the blocking plate 180 is installed
followed by the
locking screw 138. When final tightening of the locking screw 138 is
performed, the blocking
plate 180 may rigidly fix the arcuate fixation members 12C in position, and
additionally prevent
pullout of the arcuate fixation members 12C.
[0132] In another example embodiment wherein the intervertebral implant 148,
the
fixation plate 156, the blocking plate 180, and the locking screw 138 are pre-
assembled, but not
finally tightened, and then inserted into an intervertebral space before the
arcuate fixation
members 12C are inserted and driven into position, the angled posterior
surfaces 182b and
chamfered corners 184 of the blocking plate 180 may be configured to allow the
arcuate fixation
members 12C to be inserted and driven into position with the blocking plate
180 and the locking
screw 138 in place. In this embodiment, the angled posterior surfaces 182b may
have wedge
features formed thereon (not shown), the wedge features configured to
interfere between the
heads 106 of the arcuate fixation members and the surrounding structure of the
fixation plate
156, for example by applying outward force laterally upward and downward on
the arcuate
fixation members 12C to lock them in place when final tightening is applied to
the locking
screw, and additionally to prevent pullout of the arcuate fixation members
12C.
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[0133] Referring now to Figure l OJ, an example embodiment of the
intervertebral
implant system 100 in a completely assembled configuration outside of an
intervertebral space is
illustrated. The fixation plate 156 has been engaged with the intervertebral
implant 148 such that
the retaining ribs of the fixation plate 156 are seated with the retaining
grooves of the
intervertebral implant 148. Four arcuate fixation members 12C have been
inserted through
corresponding arcuate grooves within the fixation plate 156, and have been
driven to a fully
inserted position. The blocking plate 180 and the locking screw 138 have been
installed and
finally tightened.
[0134] It should be noted that although the description and accompanying
figures
illustrating the intervertebral implant system 100 included herein depict
example embodiments
of the intervertebral implant system 100 that include four arcuate fixation
members 12C, with
two of the four arcuate fixation members 12C having a generally cranial
insertion trajectory and
the remaining two arcuate fixation members having a generally caudal insertion
trajectory, other
configurations of the intervertebral implant system 100 using more or less
arcuate fixation
members 12C and/or varying insertion trajectories are possible and intended to
be included
within the scope of the instant disclosure. For example, in an alternative
embodiment of the
intervertebral implant system 100, the fixation plate 116 may have three
arcuate grooves 128
formed therein having any desirable placement and/or insertion trajectory with
respect to the
central bore 126 (e.g., with two of the three arcuate fixation members 12C
having a generally
caudal insertion trajectory and the remaining arcuate fixation member 12C
having a generally
cranial insertion trajectory, or with two of the three arcuate fixation
members 12C having a
generally cranial insertion trajectory and the remaining arcuate fixation
member 12C having a
generally caudal insertion trajectory). The intervertebral implant 108 may of
course have
matching grooves 112 formed therein. Such alternative embodiments with two
arcuate fixation
members 12C having one of a generally cranial or caudal trajectory and a third
arcuate fixation
member having the opposite general trajectory may allow for the stacking of
two or more
assembled configurations of the intervertebral implant system 100 in place of
adjacent vertebral
bodies removed from an intervertebral space. Additionally, while the arcuate
fixation members
12C illustrated in the various figures herein generally have divergent
insertion trajectories with
respect to each other, fixation plates 116 and/or 156 may also be configured
so that one or more
of the arcuate fixation members 12C will have convergent insertion
trajectories with respect to
each other, or similar insertion trajectories (e.g., laterally towards a
common side). For example,
arcuate fixation members with generally cranial insertion trajectories may
converge toward one
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another, may diverge away from one another, or may both follow similar
insertion trajectories,
while arcuate fixation members with generally caudal insertion trajectories
may converge toward
one another, may diverge away from one another, or may both follow similar
insertion
trajectories. Any combination of the above insertion trajectory configurations
may be used as
appropriate.
[0135] Referring now to Figures 1 lA to 11H, and Figures 12A to 12C, example
embodiments of additional features for securing the arcuate fixation members
12C within
assembled configurations of the intervertebral implant system 100 are
illustrated. Referring first
to Figures 1 IA to 11 H, an example embodiment using ratcheting features to
secure the arcuate
fixation members 12C is illustrated. In an example embodiment, an
intervertebral implant 148
(not shown), a fixation plate 156, and a locking screw 138 can be used in
combination with a
ratchet plate 188 configured to be received within the fixation plate 156 and
fixed in place with
the locking screw 138. The ratchet plate 188 is defined by a body 190 defining
an anterior
surface 190a and a posterior surface 190b opposite the anterior surface.
[0136] The body 190 includes a plurality of blades 192 extending outwardly
therefrom,
each blade 192 defining a proximal end 192a where the blade 192 extends from
the body 190,
and a distal end 192b opposite the proximal end 192a. In an example
embodiment, the blades
192 may be curved between the proximal and distal ends 192a and 192b. The
blades 192 may be
curved along a generally constant radius of curvature, may be curved along a
non-uniform radius
of curvature, or any combination thereof. In an alternative embodiment, the
blades may be
substantially straight between the proximal and distal ends 192a and 192b. The
blades may
configured to be of a length such that the distal ends 192b of the blades 192
are disposed within
the arcuate grooves 176 of the fixation plate 156 when the ratchet plate 188
is inserted into the
recess 172 of the fixation plate 156 in an assembled configuration. It should
be noted that while
the ratchet plate 188 is depicted within the attached figures as having four
blades 192, this
number of blades 192 is only an example configuration, and the scope of the
instant disclosure
should not be limited thereto. For example, alternative embodiments of the
ratchet blade having
more or less than four blades 192 are possible and intended to be included
within the scope of the
instant disclosure.
[0137] The distal ends 192b of the blades 192 may have tips 194 defined
thereon, the
tips 194 configured to lockingly engage with a complimentary engaging feature,
for example a
ratchet tooth 198, defined on an arcuate fixation member 12C. The body 190 may
have an
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aperture 196 formed therethrough. In an example embodiment, the diameter of
the aperture may
be slightly larger than the diameter of the central bore 174 of the fixation
plate 156, such that a
locking screw 138 may be inserted into the aperture with no interference
therebetween. In
another embodiment, the diameter of the aperture 196 may be substantially the
same as that of
the central bore 174, and the inner surface of the aperture may have threads
formed thereon, the
threads configured to engage complimentary threads of the locking screw 138.
The aperture 196
may further be defined by a concave recess 196a formed within the anterior
surface 190a, the
concave recess 196a configured to receive the convex head 142 of the locking
screw 138.
[0138] Referring now to Figure I 1D, an example embodiment of an arcuate
fixation
member 12C configured for use with the ratchet plate 188 is illustrated. A
series of ratchet teeth
198 are defined on the body 102 of the arcuate fixation member 12C. The
ratchet teeth 198 may
be defined in the area of the proximal end 102a of the body, near the head
106. The ratchet teeth
198 may be formed from triangular grooves formed within the body 102 of the
arcuate fixation
member, or may be formed on or in the body 102 using any other tooth geometry
as appropriate.
It should be noted that while the arcuate fixation member 12C depicted in
Figures 11D to 11H
has four ratchet teeth 198 formed thereon, this number of ratchet teeth is
only an example, and
the scope of the instant disclosure should not be limited thereto.
[0139] Referring now to Figuresl 1F to 11H, an example embodiment of the
intervertebral implant system 100 in a partially assembled configuration
including a single
arcuate fixation member 12C and omitting the intervertebral implant 148 is
illustrated. The
ratchet plate 188 has been nested within the fixation plate 156 and anchored
in place with the
locking screw 138. A single arcuate fixation member 12C has been inserted
through a
corresponding arcuate groove within the fixation plate 156, and has been
driven to a fully
inserted and locked position. Figures 11 G and 11 H illustrate a cross
sectional view of the
partially assembled intervertebral implant system 100. The arcuate fixation
member 12C has
been driven into place such that each successive ratchet tooth 198 has passed
over the tip 194 of
the blade 192 until the arcuate fixation member 12C arrived in a fully
inserted and locked
position. The tip 194 of the blade 192 is firmly seated against the ratchet
tooth 198 nearest the
proximal end 102a of the body 102 of the arcuate fixation member 12C, thereby
engaging the
lower surface 106b of the head 106 of the arcuate fixation member 12C against
the anterior
surface 158g of the fixation plate 156 in a fixed and locked configuration.
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[0140] Referring now to Figures 12A to 12D, an example embodiment for securing
an
arcuate fixation member 12C of the intervertebral implant system 100 with a
screw 202 is
illustrated. A plurality of helical threads 200 are defined within the body
102 of the arcuate
fixation member 12C, the threads 200 configured to engage complimentary
threads of the screw
202. The threads 200 may be defined within the area of the proximal end 102a
of the body 102,
near the head 106. In an example embodiment, the threads 200 may define
tapered threads 200a
that transition into constant radius threads 200b. The radius of the tapered
threads 200a may
decrease as the tapered threads 200a extend in a direction downward and
perpendicular from the
proximal end 102a of the body 102 until the tapered threads 200a transition
into the constant
radius threads 200b.
[0141] The screw 202 includes a shaft 204 that defines longitudinally opposing
proximal and distal ends 204a and 204b, respectively. A plurality of helical
tapered threads 204c
may extend along the shaft 204 in a direction toward the distal end 204b. The
outer diameter of
the tapered threads 204c may decrease with distance from the proximal end 204a
until the
tapered threads 204c transition into a series of constant radius threads 204d.
The constant radius
threads 204d may extend along the remainder of the shaft 204 to the distal end
204b. The
tapered and constant radius threads 204c and 204d may be configured to be
complimentary to the
tapered and constant radius threads 200a and 200b of the arcuate fixation
member 12C. In an
alternative embodiment, the threads 200 defined within the body 102 and the
threads defined on
the shaft 204 of the screw 202 may be of constant radius. It should be noted
that although the
screw 202 is depicted in Figures 12A to 12D as a set-type screw, that any
appropriate screw-type
anchor may be utilized.
[0142] When deployed in combination with the fixation plate 156, one or more
of the
arcuate grooves 176 may be replaced with a threaded arcuate groove 206. For
the sake of
simplicity, the threaded arcuate groove 206 is illustrated in Figures 12C and
12D as defined
within block 208, rather than in the fixation plate 156. The threaded arcuate
groove 206 includes
an arcuate groove 206a configured to receive the arcuate fixation member 12C,
and a threaded
aperture 206b formed adjacent to the arcuate groove 206a and configured to
guide a screw type
fastener along a longitudinal axis L4. It should be noted that although the
threaded aperture
206b is depicted as being formed to define the longitudinal axis L4 in a
direction generally
perpendicular to an outer surface 208a of the block 208, the threaded aperture
206b may be
formed to define the longitudinal axis L4 in any direction appropriate for
insertion of a screw
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type fastener. A head recess 206c may be formed within the threaded arcuate
groove 206 in the
area where the threaded arcuate groove 206 meets the outer surface 208a of the
block 208, the
head recess 206c configured to receive at least a portion of the head 106 of
the arcuate fixation
member 12C.
[0143] In the assembled configuration depicted in Figure 12D, the arcuate
fixation
member 12C has been inserted into the arcuate groove 206a and driven to a
fully inserted
position. The screw 202 has been driven into an almost fully driven position
in the threaded
aperture 206b. As the screw 202 is finally tightened, the tapered threads 204c
will engage the
complimentary tapered threads 200a of the arcuate fixation member 12C, causing
the arcuate
fixation member 12C to be locked into its fully inserted position as the screw
202 is tightened.
In the finally tightened position, the engagement of the tapered threads 204c
of the screw 202
with the arcuate fixation member 12C and the threaded aperture 206b will
secure the assembly in
place and prevent pullout of the arcuate fixation member 12C. In an
alternative embodiment, the
arcuate fixation member 12C is driven to an almost fully inserted position,
and as the screw 202
is finally tightened, the tapered threads 204c will engage the complimentary
tapered threads 200a
of the arcuate fixation member 12C, causing the arcuate fixation member 12C to
be driven into
its fully inserted position and locked with the screw and the threaded
aperture 206b. In example
embodiments utilizing a bone screw (not shown) in combination with the arcuate
fixation
member 12C, the bone screw may be inserted, for example along a trajectory
that varies from
that of the insertion trajectory of the arcuate fixation member 12C, such that
as the bone screw is
driven into its fully driven position within the underlying structure or bone,
tapered threads on
the bone screw interface with complimentary tapered threads 200a of the
arcuate fixation
member 12C and the threaded aperture 206b, thereby locking the arcuate
fixation member 12C
and the bone screw together in their finally assembled position within the
threaded aperture
206b.
[0144] In another alternative embodiment (not shown) for securing the arcuate
fixation
members 12C within the intervertebral implant system 100, a captive screw is
secured within the
central bores 126 or 174 of respective fixation plates 116 or 156. The captive
screw is
configured to be retained within its respective central bore, but be freely
rotatable therein, such
that the end of the captive screw nearest the outermost anterior surface of
the respective fixation
plate is exposed. The captive screw has engagement features formed within its
exposed end for
engaging a delivery instrument, and helical threads formed radially along its
outer surface, the
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helical threads configured to engage with a plurality of complimentary helical
threads 200
defined within the body 102 of the arcuate fixation member 12C along a
substantial length of the
body 102 between its proximal and distal ends 102a and 102b respectively. An
arcuate fixation
member 12C may be loaded tip first into an arcuate groove 128 or 176 of the
respective fixation
plates 116 or 156, such that the threads 200 near the distal end 102b of the
body 102 of the
arcuate fixation member engage with the helical threads formed on the outer
surface of the
captive screw. As rotational force is applied to the captive screw by a
delivery instrument, the
force is transferred to the arcuate fixation member 12C via the engaged
complimentary threads,
causing the arcuate fixation member to be driven into underlying structure or
bone. A plurality
of arcuate fixation members may be so loaded into assemblies comprising
respective
intervertebral implants and fixation plates before those assemblies are
inserted into an
intervertebral space. The assemblies may then be guided into position in an
intervertebral space
by a delivery instrument. Once in position, the delivery instrument may engage
the captive
screw and apply a rotational force thereto, thereby driving the plurality of
arcuate fixation
members into fully inserted positions within adjacent verterbral bodies. The
captive screw may
also lock the arcuate fixation members 12C into position within the respective
fixation plates
during final tightening of the captive screw.
[0145] Now referring to Figures 13A to 13F and 14A to 14E, example embodiments
of
delivery instruments for use in inserting intervertebral implant assemblies
constructed using
components of the intervertebral implant system 100 into intervertebral spaces
and /or driving
the arcuate fixation members 12C of the intervertebral implant system 100 are
illustrated.
[0146] As illustrated in Figures 13A to 13F, delivery instrument 208 includes
a shaft
210 that defines longitudinally opposing proximal and distal ends 210a and 2l
Ob. The distal end
210b of the shaft 210 may have helical threads 212 formed thereon, the threads
212 configured
to be received in the central bore 126 of the fixation plate 116. The proximal
end 210a may have
helical threads 214 formed thereon, the threads 214 configured to engage
complimentary threads
of an accessory (not shown). Accessories may be configured to facilitate
easier use of the
delivery instrument 208 in positioning and/or insertion of an intervertebral
implant assembly into
an intervertebral space, and may include a "pistol" grip, a handle, a slap
hammer, a slide
hammer, or the like. In an alternative embodiment, the proximal end 210a of
the shaft 210 may
have gripping features (not shown) formed directly thereon, the gripping
features configured to
enable the proximal end 210a of the shaft 210 to act as a handle.
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[0147] Delivery instrument 208 may further include a pivot block 216 having a
generally channel-shaped body 218 defined by an anterior side 218a, an upper
side 218b, and a
lower side 218c opposite the upper side. The anterior side 218a of the body
218 may have an
aperture 218d formed therethrough, the aperture enabling the pivot block 216
to be carried on the
shaft 210. In an example embodiment, the pivot block 216 maybe fixed in
position on the shaft
210. In alternative embodiments, the pivot block 216 maybe free to rotate
about a longitudinal
axis of the shaft, free to translate in an anterior and/or posterior direction
along the shaft 210,
may be releasably lockable to the shaft 210 between the proximal and distal
ends 210a and 2l Ob,
or any combination thereof. The upper and lower sides 218b and 218c may define
a channel 222
through the body between the opposing ends 218e of the body 218. The upper and
lower sides
218b and 218c may each have a pair of raised tabs 220 formed thereon at
opposing ends 218e of
the body, such that the tabs on the upper and lower sides 218b and 218c
directly oppose each
other, and are configured to receive a pair of lateral arms 224, one at each
of the opposing ends
218e of the body 218.
[0148] The lateral arms 224 each include a proximal end 224a and a distal end
224b
opposite the proximal end. The distal ends 224b of each of the lateral arms
may have an
engagement feature 226 formed thereon, the engagement feature 226 configured
to engage a
complementary engagement feature formed within the fixation plate 116. In an
example
embodiment, the distal end 224b of each lateral arm 224 may have a raised rib
engagement
feature 226 formed thereon, the raised rib configured to be inserted into a
respective aperture 122
of the fixation plate 116, and to releasably grip a corresponding retaining
rib 124. It should be
noted that a raised rib is merely an example engagement feature 226, and the
scope of the instant
disclosure should not be limited thereto. The proximal ends 224a of each of
the lateral arms 224
may be configured to be received within the tabs 220 at the opposing ends 218e
of the body 218.
The tabs 220 and the proximal ends 224a of each of the lateral arms 224 may
have apertures 228
formed therethrough, the apertures 228 configured to receive a joint connector
230. The joint
connector 230 may be a pin, an axle, a rivet, or any other appropriate
connector.
[0149] With the proximal ends 224a of each of the lateral arms 224 seated
between
respective opposing tabs 220 and with the joint connectors 230 inserted into
the apertures 228,
the lateral arms 224 become configured to pivot about the joint connectors
230, allowing the
distal ends 224b of the lateral arms to move in a grabbing motion, such that
the distal ends 224b
can releasably grip the fixation plate 116. The lateral arms 224 may be
configured to be
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simultaneously pivoted, for example through attachment to a common actuator
(not shown). The
proximal ends 224a of the lateral arms may be configured with locking features
configured to
engage with complimentary features of the pivot block 216, to enable the
lateral arms 224 to be
releasably locked in a gripping position. For example, the locking features
may comprise a
series of ratchet teeth may be formed on rounded end surface 224c of each of
the lateral arms,
the ratchet teeth configured to engage with a complimentary ratcheting
mechanism of the pivot
block 216.
[0150] Delivery instrument 208 may further include a guide ring 232 and/or a
drive
head 236 configured to deliver one or more arcuate fixation members 12C for
insertion. The
guide ring 232 and/or the drive head 236 may also be configured to be carried
on the shaft 210,
preferably between the distal end 210b of the shaft 210 and the pivot block
216. The guide ring
232 includes an annular body 234 defining a posterior surface 234a and an
anterior surface 234b
opposite the posterior surface. The annular body 234 may have a plurality of
arcuate grooves
234d formed along an inner surface 234c of the annular body 234, the arcuate
grooves 234d
configured to receive a plurality of arcuate fixation members 12C and to align
the arcuate
fixation members with corresponding arcuate grooves of a fixation plate.
[0151] The drive head 236 includes a body 238 defined by an anterior surface
238a, a
posterior surface 238b opposite the anterior surface, lateral surfaces 238c,
and upper and lower
surfaces 238d and 238e respectively. The body 238 may have a central bore 238f
formed
therethrough, such that the body 238 may be slidably carried on the shaft 210.
The drive head
236 may further include a shaft 240 having longitudinally defined proximal and
distal ends 240a
and 240b respectively. The entirety of the shaft 240 may be cannulated, the
cannulation defining
an inner diameter substantially matching the diameter of the central bore
238f, such that the shaft
240 may be slidably carried on the shaft 210. The distal end 240b of the shaft
240 may be
coupled to the anterior surface 238a of the body 238.
[0152] The posterior surface 238b of the drive head may have a substantially
concave
outer ring 242 formed therein, the concave outer ring encompassing a
substantially convex inner
dome 244. The concave outer ring 242 and the convex inner dome 244 are
configured to drive
the plurality of arcuate fixation members 12C as the drive head 236 travels
along the shaft 210 in
a direction toward the distal end 210b. In an example pre-insertion
configuration, the plurality of
arcuate fixation members 12C may be loaded into the guide ring 232 and the
drive head 236
positioned such that the concave outer ring 242 is engaged with the heads 206
of the arcuate
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fixation members 12C. As the drive head 236 is advanced towards the distal end
210b of the
shaft 210, the arcuate fixation members 12C are driven into respective
vertebral bodies. As the
arcuate fixation members 12C are driven, the heads 106 of the arcuate fixation
members 12C
travel inwardly along the concave outer ring 242 in a direction generally
towards the shaft 210,
and from the concave outer ring 242 onto the convex inner dome 244. The convex
inner dome
244 may deliver the arcuate fixation members 12C into their fully inserted
positions. The guide
ring 232 maybe removed from the shaft 210 for the final portion of the driving
process. It
should be noted that while the example drive head 236 depicted in Figures 13C
to 13E and
described herein is configured to simultaneously drive four arcuate fixation
members 12C, other
configurations are possible and intended to be within the scope of the instant
disclosure. For
example, by adjusting the geometry of the posterior surface 238b of the drive
head 236, the drive
head could be configured to simultaneously drive more or less than four
arcuate fixation
members 12C, to stagger the driving of one or more arcuate fixation members
12C, to distract
one or more arcuate fixation members 12C, or any combination thereof.
[0153] In an example method of using the delivery instrument 208 to insert and
secure
an example assembly of the intervertebral implant system 100, an
intervertebral implant 108 may
be nested an engaged within a fixation plate 116 to create an implant
assembly. The
intervertebral implant 108 may be packed, for example with bone growth
inducing substances, as
appropriate. The distal ends 224b of the lateral arms 224 may be positioned to
grip the fixation
plate 116 and the lateral arms 224 may be locked in the gripping position. A
plurality of arcuate
fixation members 12C may be loaded into the guide ring 232 and the drive head
236 moved into
position to drive the arcuate fixation members 12C. The delivery instrument
208 may then be
used to position and insert the implant assembly into an intervertebral space.
When the implant
assembly has been positioned, the arcuate fixation members may be driven into
position. The
implant insertion process may be completed with the installation of a blocking
plate 132 and a
final tightening of a locking screw 138.
[0154] Various techniques maybe utilized to actuate the drive head 236,
thereby
causing it to drive one or more arcuate fixation members 12C into position. In
an example
embodiment, the drive head 236 may be advanced towards the distal end 210b of
the shaft 210
by a series of impaction forces applied to the drive head 236. The impaction
forces may be
applied manually, for example by a surgeon via the use of a mallet, or
mechanically, for example
by a successive series of impactional strikes from a sonic hammer. In an
alternative
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embodiment, the drive head 236 may be advanced via a mechanical drive system.
For example,
a rack and pinion system may be employed, as illustrated in Figure 13F. A rack
246 includes a
proximal end 246a and a distal end 246b opposite the proximal end, the distal
end 246b coupled
to the drive head body 238 and/or the shaft 240. The rack may have a series of
teeth 248 defined
thereon between the proximal and distal ends 246a and 246b. The pivot block
216 may have a
guide channel 250 formed within the upper side 218b of the body 218, the guide
channel 250
configured to slidably receive the rack 246 therein. A pinion drive 252 may be
coupled to the
pivot block 216, for example on the anterior side 218a of the body 218, such
that one or more
pinion gears (not shown) of the pinion drive 252 engage the teeth 248 of the
rack 246. The
pinion drive 252 may be configured with a manual actuator 254 and/or an
adapter 256, the
adapter 256 configured to couple with a motorized source of rotational force.
When the pinion
drive 252 is actuated, via either the manual actuator 254 and/or a rotational
force applied via the
adapter 256, the rack 246, and consequently the drive head 236, may be
translated in a direction
toward the distal end 210b of the shaft 210, such that the arcuate fixation
members 12C are
driven into position.
[0155] Referring now to Figures 14A-14E, delivery instrument 278 includes a
pair of
insertion rods 258, each defining longitudinally opposed proximal and distal
ends 258a and
258b. The distal ends 258b of the insertion rods 258 may be have engagement
tips 258c formed
thereon, the engagement tips 258c configured to be received by a fixation
plate. In an example
embodiment, the engagement tips 258c may define an outer diameter differing
from the outer
diameter of the distal ends 258b of the insertion rods 258, such that the
outer diameter of the
engagement tips 258c are uniquely sized to be received within the bores 178 of
the fixation plate
156. The engagement tips 258c may have an engagement feature 258d formed
thereon, the
engagement feature 258d configured to releasably lock the distal ends 258b of
the insertion rods
258 within the fixation plate 156. In an example embodiment, the engagement
feature 258d may
be a raised rib designed to engage with the retaining shelf 166 of the
fixation plate 156 when a
respective insertion rod 258 is inserted into the fixation plate 156 and
rotated into a locked
position. In alternative embodiments, the insertion rods 258 may be locked to
the fixation plate
utilizing other engagement features 258d, for example a ball and detent
mechanism installed
within the engagement tips 258c of the engagement rods 258, a series of
gripping teeth defined
on the engagement tip 258c, etc.
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[0156] The insertion rods 258 may each have a channel 260 formed within the
surface
thereof between the proximal and distal ends 258a and 258b, the channels
configured to directly
oppose each other, facing inwardly, when the insertion rods 258 are locked in
place within the
fixation plate 156 in an assembled insertion configuration. The channels 260
may be configured
to slidably receive lateral wings 276 coupled to the body 238 and/or the shaft
240 of the drive
head 236, such that the drive head may translate between the proximal and
distal ends 258a and
258b of the insertion rods 258 when the lateral wings are received with the
channels 260. The
channels 260 may be augmented by drop-in bores 262 formed within the outer
surfaces of the
insertion rods 258, the drop-in bores 262 configured to allow additional
components of the
intervertebral implant system 100, for example the drive 236 configured with
the lateral wings
276, to be inserted into the channels 260 when the insertion rods 258 are
already in an assembled
configuration. Gripping features 264 may be formed within the outer surfaces
of the insertion
rods 258 between the proximal and distal ends 258a and 258b, the gripping
features 264
configured to facilitate easier gripping of the insertion rods 258, for
example as they are rotated
into a locked position within the fixation plate 156.. In an example
embodiment, the gripping
features 264 include a series of longitudinal grooves formed radially around
the outer surfaces of
the insertion rods, although any other gripping features may be used as
appropriate. The
proximal ends 258a of the insertion rods 258 may be configured to be received
and lockably
engaged within posterior bores 268 of an end block 266. For example the
proximal ends 258a of
the insertion rods may have one or more apertures (not shown) formed
therethrough configured
to accept a pin or other connector, may be have threads formed thereon
configured to engage
with complimentary threads formed within the end block 266, and so on.
[0157] The end block 266 maybe defined by an anterior surface 266a, a
posterior
surface 266b opposite the anterior surface, lateral surfaces 266c, and upper
and lower surfaces
266d and 266e. Posterior bores 268 may be formed within the posterior surface
266b of the
block 266, the posterior bores 268 configured to receive the proximal ends
258a of the insertion
rods 258. Opposing rod grooves 270 may be formed within the end block 266, the
rod grooves
270 bounded by the lower and laterally facing quadrants of the posterior
bores, extending
outwardly to the lateral and bottom surfaces 226c and 266e respectively. The
rod grooves 270
may be configured to allow the insertion of retaining members 272 through the
rod grooves 270
and into the proximal ends 258a of the insertion rods 258. The retaining
members 272 function
to secure the insertion rods 258 within the posterior bores 268, while still
permitting the rotation
of the insertion rods 258, as limited by the lateral and lower facing surfaces
of the rod grooves
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270. The retaining members 272 may be, for example, pins, posts, screw-type
anchors, or the
like. An accessory bore 274 may be formed within the anterior surface 266a of
the block 266,
the accessory bore 274 configured to receive an accessory. The inner surface
274a of the
accessory bore 274 may be configured with engaging features, for example
helical threads,
configured to engage complimentary engagement features formed on an accessory.
Accessories
may be configured to facilitate easier use of the delivery instrument 278 in
positioning and/or
insertion of an intervertebral implant assembly into an intervertebral space,
and may include a
"pistol" grip, a handle, a slap hammer, a slide hammer, or the like.
[0158] In an example method of using the delivery instrument 278 to insert and
secure
an example assembly of the intervertebral implant system 100, an
intervertebral implant 148 may
mated with a fixation plate 156 to create an implant assembly. The
intervertebral implant 148
may be packed, for example with bone growth inducing substances, as
appropriate. The
engagement tips 258c of the insertion rods 258 may be inserted into and locked
in place within
the fixation plate 156. In an example embodiment, the insertion rods 258 are
locked into place
by first inserting the engagement tips 258c into the fixation plate, then
rotating the insertion rods
258 one quarter turn to engage the raised ribs 258d with the retaining shelves
166 in the fixation
plate 156. The delivery instrument 278 may then be used to position and insert
the implant
assembly into an intervertebral space. When the implant assembly has been
positioned within
the intervertebral space, the lateral wings 176 of the assembly carrying the
retaining ring 232 and
drive head 236, along with one or more pre-loaded arcuate fixation members
12C, may be placed
into position in the channels 260 via the drop-in bores 262, and slid into
position so that the
arcuate fixation members 12C are aligned with the arcuate grooves of the
fixation plate 156. The
arcuate fixation members may then be driven into position. The implant
insertion process may
be completed with the installation of an optional blocking plate 180 and a
final tightening of a
locking screw 138.
[0159] Various techniques maybe utilized to actuate the drive head 236,
thereby
causing it to drive one or more arcuate fixation members 12C into position. In
an example
embodiment, the drive head 236 may be advanced towards the distal ends 258b of
the insertion
rods 258 by a series of impaction forces applied to the drive head 236. The
impaction forces
may be applied manually, for example by a surgeon via the use of a mallet, or
mechanically, for
example by a successive series of impactional strikes from a sonic hammer. In
an alternative
embodiment, the drive head 236 may be advanced via a mechanical drive system.
For example,
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a rack and pinion system may be employed, as illustrated in Figure 14E. A rack
246 includes a
proximal end 246a and a distal end 246b opposite the proximal end, the distal
end 246b coupled
to the drive head body 238 and/or the shaft 240. The rack may have a series of
teeth 248 defined
thereon between the proximal and distal ends 246a and 246b. The end block 266
may have a
guide channel formed within the upper surface 266d, the guide channel
configured to slidably
receive the rack 246 therein. A pinion drive 252 may be coupled to the end
block 266, for
example on the upper surface 266d, such that one or more pinion gears (not
shown) of the pinion
drive 252 engage the teeth 248 of the rack 246. The pinion drive 252 may be
configured with a
manual actuator 254 and/or an adapter 256, the adapter 256 configured to
couple with a
motorized source of rotational force. When the pinion drive 252 is actuated,
via either the
manual actuator 254 and/or a rotational force applied via the adapter 256, the
rack 246, and
consequently the drive head 236, may be translated in a direction toward the
distal ends 258b of
the insertion rods 258, such that the arcuate fixation members 12C are driven
into position.
[0160] It should be appreciated that a variety of kits can be provided that
one or more
components of the fixation system 10 or the intervertebral implant system 100.
The components
of the kits may be configured the same or differently. For example, within a
single kit, arcuate
fixation members 12A, 12B, and/or 12C may be provided that have varying
lengths, differing
radii of curvature, differing head and/or tab configurations, differing cross
sectional geometries,
and so on, depending for example on the type of procedure being performed by a
surgeon, or on
the particular anatomies of individual patients. The kits may also be
configured differently with
respect to which components of the individual systems are included in the
kits. For example, a
kit of the fixation system 10 may include arcuate fixation members 12A and/or
12B with varying
configurations and/or features, and may or may not include guiding members 14,
and other
fixation components such as fixation rods and the like. In another example, a
kit for the
intervertebral implant system 100 may include arcuate fixation members 12C of
varying lengths,
radii of curvature, and/or features, and may include one or more of
intervertebral implants 108 or
148, fixation plates 116 or 156, blocking plates 132 or 180, ratchet plate
166, or locking screws
138. Example kits for the fixation system 10 and the intervertebral implant
system 100 may also
include the respective delivery instruments 66, 208, and/or 278.
[0161] Although arcuate fixation members and the other components of the
fixation
system 10 and the intervertebral implant system 100 have been described herein
with reference
to preferred embodiments or preferred methods, it should be understood that
the words which
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WO 2010/121028 PCT/US2010/031244
have been used herein are words of description and illustration, rather than
words of limitation.
For example, it should be appreciated that the structures and/or features of
components of the
fixation system 10 may be combined with or otherwise integrated with the
structures and/or
features of the intervertebral implant system 100, unless otherwise indicated.
Furthermore, it
should be noted that although the fixation system 10 and the intervertebral
implant system 100
have been described herein with reference to particular structure, methods,
and/or embodiments,
the scope of the instant disclosure is not intended to be limited to those
particulars, but rather is
meant to extend to all structures, methods, and/or uses of the fixation system
10 and the
intervertebral implant system 100. Those skilled in the relevant art, having
the benefit of the
teachings of this specification, may effect numerous modifications to the
fixation system 10
and/or the intervertebral implant system 100 as described herein, and changes
may be made
without departing from the scope and spirit of the instant disclosure, for
instance as recited in the
appended claims.
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